Ok, I've worn contacts since I was 16 and a close family friend runs an vision correction practice.

First of all, NEVER put non-contact rated drops in if you're wearing contacts. Depending on the specific recipe in the drops and the material of your contacts, you could be breaking down the compounds in the lenses and the result can be absorbed into your tissues and eye. It can cause severe irritation and in my case, a raging migraine-like headache.

Plain old saline solution is fine to flush your eyes with (wearing contacts or not), but know that straight saline is not a lubricant, and when you flush your eye you are also getting rid of a lot of natural fluids and mucous your body normally produces to protect your peepers.

Best bet is to use something specifically made for refreshing contacts, they usually have a form of silicone that acts as a lube, and the buffers and surfactants in them won't fubar the plastic compounds in your lenses. The only thing weird that I've found with these is that they make your eyes feel a little more 'gluey,' and by that I mean you can accumulate more eye grit in the corner of your eye.

...my $0.02


Edit: Oh and putting contact-drops in your eyes when not wearing contacts is perfectly safe.