|Audio Tape Digitisation Workflow
The tape must be in very intimate contact with the heads in order to get good results. Dirt particles may easily cover the magnetic head gap, which causes additional loss in the playback signal.
Clean tape heads, tape guides, idlers, and capstan. Use isopropyl alcohol on a cotton swab. If there is anything that will not come off with this method, consult an expert! For rubber parts, do not use isopropyl alcohol, but plain water (and perhaps a drop of dishwashing liquid).
Tape Recorder: Head Cleaning
Introduction to Sound Recording: Cleaning and demagnetizing
Analog Tape Recorders