I haven't wasted any. A batch can almost always be saved. What was wrong with the batches you threw out?
Technically I've only thrown out the first one....I didn't let it trace long enough and when I went to check it in the mold 2 days later, all the oil had risen to the top. My soapmaking book said that what was left would be too caustic to use, so I tossed it. I tried the same recipe again (it's a goat's milk recipe), and while it did fully trace and hardened in the mold, it's a funky color and smells kind of...I don't know...not pleasant. None of the essential oils I used in it came out, and I don't know if the milk was about to turn and that's what's causing the smell. I thought about rebatching it, but if the milk went rancid, probably not a good idea.