Phyllis -- There's no reference to "AI" or "AIS" on Nikon lenses. I think it was after 1977, that everything new was "AI." At the time, you could get original Nikon lenses "AI'd" for anywhere from $14.95 to $45 or so -- it depended on the lens. But again -- nowhere does it say "AI" on the lens. And the lenses that were "hacked" into "AI" lenses didn't get the new ring with the smaller-lettered f/stops. If you ever see one, they usually have a paper or other material "stick-on" with the small f-stops. You could see the f/stop through the viewfinder via an optical system and "window" at the bottom of the prism housing.
Compressed air? -- send someone to WalMart or any office supply store. They'll have it for sure. Just don't spray in into the back of the lens where it might get inside. The stuff includes fine liquid mist sometimes.
I'm sure you'll be able to clean the lenses up and be back in business. The fluid is probably alcohol. Don't use rubbing alcohol though -- it contains oil. It may take some patience -- and a few q-tips, and maybe some wooden toothpicks for cracks and crevices! Then the focus dot in your viewfinder will indicate focus, as it works off of contrast vice any physical measurement.
BTW, my first Nikon used neither F-mount or AI lenses. It was my Dad's rangefinder Nikon S.