I use Windex on pinch rollers and use rubber conditioner only once in a while, which is really how rubber conditioner/restorer was intended to be used. You can overdue it with chemicals on Urethane rubber, so don’t use it daily.
I’ve used the old TEAC rubber conditioner since about 1979 and I still have about ½ oz left of an old 2 oz glass bottle. That’s how far it goes when used in moderation. That was my favorite for pinch rollers. The bad news is TEAC doesn’t sell it anymore. The good news is it was made for TEAC by Rawn and they still sell the latest incarnation as “Re-Grip” They changed the formula a couple times because someone in California found some chemical in it to be carcinogenic. But none of my tape decks have gotten cancer, so I guess the joke’s on California.
http://www.aedwis.com/rawn.html
I use denatured alcohol on heads and tape guides, but not on rubber. The old GC Electronics Tape Recorder Head Cleaner (#30-124-1) was denatured alcohol. They have something similar called VCR/Magnetic Head Cleaner (#19-5302), but I’m not sure what it has in it. I would call and find out but since I just buy 32 oz cans of Klean-Strip denatured alcohol at Lowes or Home Depot for $3.99 I’m not too motivated to find out. I just keep refilling my 15-year-old glass bottle of GC head cleaner from the can.
99% isopropyl is fine as well. If you can’t find one type, then use the other. Either type will get the job done.
One little tip… make it a practice to clean right after a session rather than right before the next session. That way you don’t have tape residue and other particles sitting around on your tape path for extended periods of time. You want to leave a clean machine as you turn out the studio lights for the night.