I find it strange when folks use a good product then denigrate it when it does it's job. Tri-Flow oil has solvents it it. It also has PTFE in it. The solvents will dissolve the old oils but you have to clean the residue off then reoil the parts. The combination of dissolving the old lube and the PTFE might be the residue left behind.
I use regular SM oil in the motors. I use Tri-Flow every where else. I have used it on 100 year old machines all the way up to machines made in the 90s and have yet to see any evidence of paint removal.
I don't have any musical instruments to use it on, but I do have a couple of vintage mechanical and one electric typewriters I'm going to use it on. I expect the typewriters will work much better afterwards.
The ONLY con I find with Tri-Flow is you shouldn't use their grease in Singer motors. What makes it great on gears is the same thing that makes it unsuitable in motors.
Joe