Recently, my violin's sound wasn't coming very well. I searched it on Google, and found out it was because of rosin build up on my strings, a common case. What is the best way to treat rosin build up on the strings?
Rosin can be easily and safely cleaned from strings with isopropyl (rubbing) alcohol. Put a bit on a rag and wipe the strings with it. Be very careful not to drip any alcohol on the instrument, though.