90% isopropyl alcohol or more nothing less and certainly not rubbing alcohol, as they add all kinds of stuff to that. Use it on pinch rollers, capstan and heads.
Clean after 4 or more tapes, maybe more depending on how what the tape leaves behind. I use ear swabs.
I also have some rubber revitalized that can be used on belts and the pinch rollers. But you have to let that soak in overnight. Afterwards, I give it a light cleaning to remove any left over residue.