Ethanol and Acetone here.
I mix 50/50 AR quality Ethanol and deionised water to clean lenses. It's often occured to me that if I went out and bought a bottle of 100 degree proof Smirnoff it would probably do the same job... don't think the boss would authorise the Purchase Order though
Other stuff I use is Potassium Hydroxide nasty, nasty stuff- got to treat that with a lot of respect!
Oh and Amonium Hydrogen Difluoride which is nasty too.