After reading the fine print warnings on the label (much first aid advice on what to do if the patient stops breathing after coming into contact with the solution...) we carefully put a couple of drops of cleaning solution on the tape, put the cassette  in the player, and listened as it choked and ground and clicked, and then refused to come out when I hit 'eject.'  In the process of wrestling the cassette out of the player, the tape broke.  Hoping that the few seconds of cleaning had done some good, we then put in a regular tape, which DID play better for a few minutes, then quickly faded.