Okay, I just cleaned and de-labeled six cases of really cruddy (but free) old bottles that are now as good as new and I think I've perfected my system. I was really happy with the ease and relative speed, and ALL of the bottles now look brand-new.
First, I fill a large plastic tub with bleach water (in our actual bathtub so that I can't bleach anything else) and let the bottles soak for a while to kill the mold and anything else that's in them. Then I use a large bucket to carry the bottles to the kitchen, where I load them into my dishwasher and start the hottest wash setting I have (while this is going I start soaking more bottles in the bleach solution). Running the hot wash for about 30-45 minutes loosens or even steams off the labels and also loosens any remaining crap (just a figure of speech, Appleman). Hot water also completely neutralizes the bleach. I then use a kitchen knife to scrap off labels that are still stuck, polishing off any remaining glue by using a kitchen scrub pad under running water. This sounds like work but the labels are so soft at this point that it takes about five seconds, and I'd say this method completely cleans 99% of the bottles. For the really stubborn gummy label bits on the last 1%, I use first "goo gone" and then, after rinsing, a brillo pad, and this completely cleans them.
Final step is a good bottle-blasting, which gets rid of any remaining mold or other crap (again, just an expression) on the inside of the bottle. After being bleached, heated and bottle-blasted even the most stubborn mold typically flies right off. Out of six cases yesterday, I had only two bottles that some sort of insect had nested in and the egg cases wouldn't all come off right away (ew! this is not a story that drinkers of my wine need to know). Because I don't have any scrubbing equipment for the inside of the bottle, for the two stubborn bottles I repeated the bleach-soak with a stronger solution, left it overnight and bottle-blasted them away.
So - that's what works for me, but I think there are a lot of effective recycling systems out there and different ones work best for different people. Good luck.