Reel-to-Reel care?

Greetings, Does anyone have some "care and feeding" tips for vintage reel-to-reel tape drives? I've recently purchased a couple nice 9 Track drives, and want to make sure they (and the media) last as long as possible. I've already given the heads, rollers and guides a good cleaning with 99.9% anhydrous Isopropyl Alcohol using 'fuzzless' cotton cleaning sticks, and plan to do so on a regular basis. Is there such a thing as too much cleaning? ;) What other tips and tricks should I know? For example, should I always unload and store the tapes in their carriers immediately after I'm done using the drives, or can I safely leave them loaded for an extended period (oxidization? de/magnetization? deterioration?). They definitively look cooler with tapes loaded :) Thanks, Ken C.