how to fix distorted audio on your car's cassette player, using head cleaner tape 

simple video, may be self explanatory but wanted to show it anyway.
unfortunately, this didn't work for me, I will likely have to remove the tape deck mechanism itself and service it outside of the head unit. but if you have a cassette player that plays too slowly or too quickly, or the sound is muffled or distorted, using a cleaner tape like this should do the trick.