Hi wjm,

What may be needed to be done is opening the radio to access the tape section and manually clean the head and capstans (metal posts) and rollers (since you are there). Two type of chemicals can be used to clean them. This all depends on what got on the parts. If coke or coffee is on it then use Windex or the like since alcohol will just wipe on and wipe off with no effect. If you have carbon or other type of build up then an alcohol solution should work. Try both of these if you are not sure. No harm if it doesn't need one or the other.

Cleeve Morrison
La Jolla Audio Repair

www.lajollaaudiorepair.com