What is the best liquid for cleaning the screen of a digital camera?

Have a look at this.
http://www.shopzilla.com/8B--Digital_Cam...

spray windex on a cloth and wipe the screen

Usually a damp piece of clean lint-free cloth is the best.

You should not use harsh chemicals. A microfibre cloth or glass cleaning cloth and a tiny amount of water (a drop or two) are all that you need

lens cleaner for plastic eyeglasses. very inexpensive .
It should for plastic because the lens on this new age of cameras are whatever form of plastic (no longer fancy rare glass) unless
you still have o prefer film cameras, high end of course.

Clean chamois. This is what I will use if I have to. Make sure it has no chemicals and chamois is lint free.

Lens should not be wiped often. There is a coating on them. If you wipe it, you will spoil them. My 2 cents worth. I never wipe and if I have to, I will do it very ............c a r e f u l l y.

After you wipe clean, take good care of them NEVER ever touch them - even if you think your fingers are clean. Your body oils are always present and that will smudge.

There is really no safeway to clean camera lenses, they are so delicate. Taking care of them (literally give your life to it) is the only way.

DO NOT use windex. or any other household chemical cleaning solution. use a lens cleaning solution. they are widely available at any drug store for cleaning eye glasses, camera lenses, monitors, etc. they come in different packages under different names but they are all pretty much the same thing. namely, a silicon based anti-static solution that cleans and prevents dust from catching on the screen, lens, etc. use a lens cleaning cloth as well. also available at any drug store. kleenex tissue works in a pinch but it's not recommended.