We see lots of Internet Advice™ on how to remove excess rosin from gut strings: soaking in oil, soaking in mineral spirits, scraped with sandpaper or steel wool, wiping down with lemon juice, rubbed with olive oil-soaked licorice(?), placed in an oven(?!?), and on, and on.

It is NOT recommended to use alcohol or other liquid solvents to remove rosin from gut strings, as it will cause the material to physically break down reducing the lifespan of the string (and even damage the lacquer of an instrument).

The above being said, the best way to remove rosin buildup on strings is with denatured alcohol. This will remove the rosin and leave no residue on the string. Remember to use an almost-dry cloth to avoid dripping on the instrument or soaking the string. Removing a little at a time is the best way to go.

We do NOT recommend using sand paper on a gut string. Sanding a varnished string will remove some or all of the varnish, and sanding a plain gut string can effect its structural integrity. A nail clippers is the safest way to carefully cut stray gut hairs. 

Some people insist on using oil (or even deer tallow?) to wipe down strings, but we have not found it to be useful. If you insist on the need to use oil on your gut strings, almond oil is the least detrimental as it leaves behind little residue and will dry completely — versus something like olive oil which does not dry completely and can lead to strings becoming gummy. 

Gamut Music does NOT recommend soaking strings in oil or any other solution as it may cause the material to expand internally and/or break down the bonds within the string.