I found 2, 3 year old bottles of Cologne, are they okay to use?

If they smell fine to you go ahead and use them. Colognes are made from oils so the worst that could happen is that they could weaken in scent or start to smell odd. If you sniff the bottle and it smells okay I don't see any reason not to use them. If they were kept in a wardrobe out of sunlight they are probably alright.