Kodak and others recommend Isopropyl Alcohol, as high a concentration as you can get. You can find 91% rubbing alcohol in drug stores, and I have used it before. Also, go to a photo store or on line place and they have neg cleaning solutions made for film (use with cotton balls). A small bottle of either should last your life time, but water marks from drying may not come off.
You can search this forum for "Alcohol and Negatives" and find other threads and posts.