The CD player is always the first thing to go. I believe there was a class action suit against Aiwa a while back because they would fail within two years with heavy use.
If the unit has an aux input then get a cd player.
sometimes it reads it but it takes hours to start the song.
You are a very patience man.
U can attempt to use one of those disc cleaners, they have tinny brushes on them, but if that doesn't work, it needs professional help, which may not be worth it these days, Walmart often have them for $30.