Carb cleaner works well, BUT: It melts plastic! So it's probably OK on very old tuners, but by the late 50s, watch out. It might melt the moving parts of a tuner into a blob
. Also it will melt little craters into wood finish, paint, and aluminum in some cases.
But it definitely does do a great job cleaning. It even gets cigarette smoke off, which I've seen badly detune a variable cap tuner.
Charles