Accidents
Never attempt to repair an instrument unless you are a professional!

Bow Care
Never touch the bow hair with your fingers. Natural oils on your skin will damage the hair. Make sure you do not over-tighten the bow hair, and always loosen the bow tension after playing.  Rehairing: A very freshly rehaired bow may produce more side noise (a hissy or gritty sound) than a bow that has been “played in”.  Sound: Two things can influence a bow’s sound quality.  The type of rosin and the type and quality of the bow hair.

Bridge
A correctly maintained bridge can last for many years. The position of the bridge is very important. The back side of the bridge should stand at a right angle to the top. The feet of the bridge should be seated evenly on the top.  Problems with bridges occur mainly when strings are loose and need to be tuned.  Adjustment: Always have a professional adjust the bridge.  String Height: The bridge can be adjusted according to the player’s preference. 

Cases
In general, cases with suspension are preferable. Suspension means that the case is in contact with the instrument at the upper and lower (neck and chinrest area), leaving most of the instrument suspended in the air. In a non-suspension case, the main contact point with the instrument is at the center of the back, where the sound post stands. A strong impact to the case can create a post crack in the top or back.  To keep the bridge from hitting the inside of the case, make sure the instrument has straps that hold the neck down. Also, make sure the bows are secured in the case to prevent instrument damage.  Inside your case:  Suggested items to store in your case include the following: rosin, spare strings, pencil, cloth, tuning device, and chinrest.  Secure items in your case so they will not rattle around and cause possible damage to your instrument.

Cleaning & Polishing
Always wipe the rosin from the instrument and wood of bow before putting them away. Both the instrument and bow easily pick up dust, rosin, oils, and dirt, and it is best to clean them with a cloth (something that is lint-free and will not scratch the instrument). Make sure to wash the cloth regularly, as dirt and rosin build up.  Make sure you do not use commercial cleaners on your instrument (pledge, etc.) They often contain solvents and abrasives that can damage the varnish.

Holding & Handling your instrument
Never leave your instrument on a chair or allow it to lean on anything.  Always leave the instrument in its case.  Always loosen the bow when finished playing. Leaving the hair tight will warp or break the stick and will also cause the bow hair to stretch.  

Humidity
During low humidity, cracking may occur. Use a Dampit or humidifier in your instrument when humidity is below 35%.  Keep the instrument away from radiators or other heat sources. 

Insurance
All instruments and bows should be insured against damage. This can be done on a homeowner’s or renter’s policy. Be sure to ask for an “all risks” or "marine rider" policy that will cover loss in case of a fire or theft.

Pegs
Your instrument’s pegs may slip from time to time, which is not necessarily an indication that the pegs do not fit; pegs shrink when humidity drops. Turn the peg with normal pressure into the hole. Never force a peg into the hole when the peg is slipping, because it may crack the peg box. If the peg still does not hold, it may be too lubricated. In this case, remove the peg and wipe off the excess lubricant with paper tissue and denatured alcohol.  Your instrument’s pegs may also stick at times. In this case, lubricate them with peg compound, but use it sparingly because it may build up and cause the pegs to slip. If the pegs are too tight due to swelling from increased humidity, don’t try to tune them up. The peg might suddenly move and you will break the string. If you use more force than usual, apply it in the downward portion and pull the peg out as you turn it- then try to tune it up again. In most cases, it is always best to let a professional help to prevent any damage to your instrument. 

Rosin
Rosin selection depends on the individual player and the particular instrument.  Dark rosin will provide more grip and stick than light rosin and is usually preferred by cellists.  Bass rosin is usually found in 2 varieties, a soft, sticky, light rosin like Pops or a harder, dark Swedish style rosin like Carlson.  The new green or jade rosins are also very popular. 

Soundpost
The soundpost is made of spruce and transfers the vibrations from the top of the instrument to the back. It is located inside the instrument, below the treble foot of the bridge.  Adjustment:  The tops and backs of instruments expand and contrast depending on the humidity. This causes the soundpost to be either too tight or too loose, resulting in sound variation. Most of the time, the instrument will return to normal. If not, the soundpost may need to be adjusted. *The soundpost should never be adjusted by anyone except a professional. 

Strings
Common reasons strings break

*If you are tuning the string above the correct pitch
*If the string slots in the bridge or top nut are too narrow or deep
*If there are imperfections in the wood of the bridge
*If a string is pinched against the side or bottom of the peg box
*Fine tuners with sharp edges, very common with Hill style loop end fine tuners

If you have a particular string that breaks often note the area of the break (ie. nut, bridge, peg, fine tuner) to determine if the problem is in that area.

String Replacement
Strings should be replaced at least once a year (depending on how much time is spent playing), although steel strings may last longer than this. If you notice any of the following, you most likely need a new string: irregularities in the winding, dull or dead sound, or fifths out of tune when playing a finger straight across two strings. Also, when strings are worn out, they become flat at the bottom (the side that faces the fingerboard). When this happens, the string needs to be replaced.  Always remove and replace only one string at a time. Removing more than one may cause the sound post to fall.  When replacing a string, first thread it through the tailpiece or fine tuner. Push the upper end of the string through the peg hole so that about half an inch protrudes from the other side. While pulling the slack out of the string, wind the string around the peg. Be careful not to turn the peg too much, because the string will break.  Sometimes with older or inexpensive hardwood pegs the hole in the peg that you insert the string into may be off center and against the edge of the pegbox with the string impeding the tightening of the string.  Have a professional reset the string hole to a centered position.

String Selection
The brand of strings you select for your instrument can have a dramatic effect on the sound. Some strings produce a brighter sound, while others produce a sound that is darker. Not every string reacts the same on every instrument.  For some instruments, a full set from one manufacturer often works fine, but at times it is necessary to use different brands to achieve an even sound. For example, the upper strings on instruments will often sound brighter than the lower, so it is popular to use a brighter string on the lower register.  Steel strings are more common on student instruments and usually require fine tuners on all strings.  Steel strings usually pull to a higher tension than perlon or synthetic type strings and have a brighter and sometimes louder sound.  Fiddlers may prefer steel but some also use perlon strings.  Vassar Clements used Tomastic Dominant perlon strings with a Piastro gold labeled e string, one of the most commonly used string set ups for all players.  Perlon or synthetic strings have a mellower, sweeter sound and usually pull to less tension than steel strings.  Perlon strings are easier to press down on the fingerboard and are preferred for more delicate instruments.

Temperature
Always keep the instrument at room temperature whenever possible. Hot temperatures cause the wood to expand, dry out, and crack. Cold temperatures cause the wood to contract, and crack.  Do not leave your instrument in an automobile and do not expose the instrument to direct sunlight. The inside temperature of a vehicle can reach up to 150 degrees!

Transporting your Instrument
Always make sure the case is fully latched and zipped before picking it up. Cellos should be carried in an upright position against the body- not down.

Troubleshooting Buzzes & Rattles
Here are some of the most common causes:

Contact between tailpiece and chinrest, saddle, or top- adjust the chinrest slightly to the right or left, or insert a small piece of cardboard in the narrow area between the tailpiece and saddle/ top

Endpin- there could be a loose screw (on a cello or bass)- all endpins are different
Fine tuner vibrating- undo the tuner screw, insert two pieces of thread into the hole, screw the tuner back, and trim any excess thread
Jewelry or buttons in contact with instrument- separate with a cloth
Loose decorative pin in tuning peg- remove the tuning peg and pin. using a toothpick, insert a very small amount of white glue into the hole. reinsert the pin and hold for twenty seconds
Loose chinrest mountings- tighten slightly with a chinrest key
Loose sliding mute- slide the mute down over silk windings
Loose wolf eliminator- slightly tighten the screw
Open Seam- take instrument to a professional 

Tuning
Instruments are tuned using the fine tuners and the tuning pegs. If the instrument is really out of tune, use the tuning pegs to the approximate pitch. Next, use the fine tuners to make small adjustments. Fine tuners should be kept in the middle range position, not too far in or out. When the fine tuner is most of the way out, reset it to the middle position and use the tuning peg to tune the string.  Make sure, when tuning your instrument, you do not go above the correct pitch of the string. This is one of the most common ways to break strings.