Hercules says that they have conducted extensive research into the effect their SSF has on all of the main guitar finishes. According to them, they have had no adverse effect on Nitrocellulose finishes, although some people claim to have had their finishes spoiled due to being in contact with SFF for too long. Hercules also acknowledges that each guitar manufacturer uses a slightly different formula for their Nitro finishes. Therefore it is impossible to test them all. We would highly recommend researching your particular guitar’s manufacturer and whether the SFF may react, should you have an instrument with a Nitro finish.