How to Clean Audio Cassette Heads

I bought a used AM/FM/Cassette deck for my car. Unfortunately, the
heads, capstans, and pinch rollers were filthy. A cleaning tape barely
made a dent in the grime, so I cleaned everything gently with Q-tips and
rubbing alcohol. But there is still visible corrosion on the tape head,
causing playback to sound muffled (in one direction only; in the other
direction, the music sounds fine; it's a reversible deck). I have run
the (wet) cleaning tape through the machine about 15 times, to no

Does anyone know of a safe method to remove corrosion from audio
cassette tape heads? Not sure if I'm savvy enough to try to remove the
tape head from my old player and put it in the new player. Maybe I just
need to buy another used deck from a more reputable seller.

Many thanks.

Farmer Bill