Fixing flakey floppies

Greetings, I have three flakey floppies. I wonder if they are worth fixing. Two are TEAC FD-55FRs. One appears to not report the INDEX mark, the other works well until around track 35 or so then fails... The third floppy is a 1.2 MB YD-380. It won't reliably move the head... I've tried cleaning the heads (which rehabbed a forth drive: a TEAC FD-55GFR) on these drives a few times. I'm thinking that it's too much hassle and I should just trash them, at least the YD-380. I have 3 1.2MB drives that work. The 55FRs are desirable to have working since I can put them in a Rainbow, but even at ebay prices it isn't worth more than an hour of my time to rehab. Before I do that I thought I'd see if there was something simple I can do. I did all my testing with the kryoflux board on a known-good disk (720k 5.25" drive so it tests both sides at the normal density and tests all 80 tracks w/o using the high density mode so the FRs can read it). Warner