[Leo.G (Leo)]

Other than acetone or heat (not recommended on lenses) I know of nothing else which will help.
It's not that there likely isn't anything else it's the risk of damaging the glass and mechanisms, perhaps some isopropyl alcohol may loosen them, I do not know but it won't destroy the lens.


Actually, I might.
Recently while trying to remove a battery cover from an old Miranda camera I recently came into possession of, I found a hint online. I already knew cans of compressed air are just refrigerant but I read about it on a camera site where someone suggested using a little of the liquid (turn can upside down and gently press nozzle to get liquid) and try and spray it directly (sorry, drip it) on the screw heads. After a few applications the screws MAY shrink enough to loosen the binding on the threads. Worth a shot. Maybe put a small ring of double sided tape or plasticine or anything to form a small reservoir for the refrigerant to pool.
It worked on the battery cover.
It's funny, my son and I had already played with making a full octave set using empty water bottles and this liquid. The bottles have to be struck with a small hammer (from my xylophone) but they sound amazing.

If it helps with these little things I buy the packs of diabetics syringes at the local pharmacy, cheap and convenient when you need precise control to apply oils and solvents in small quantities though I'm sure you'd probably already know this. Yes, I stab myself nearly every time I use the rotten things too no matter how careful I am, I'm surprised I haven't caught some nasty infections up to now.