Oh no! I definitely suggest deflocking. But it can be difficult. I have a deflock I'm working on myself at the moment. I hope she turns out beautifully for you!
Sorry to hear. I don't use oxyclean on ANY ponies. Too many horror stories. Yet people keep recommending it to clean ponies, especially people who are new to the collecting community and chime in on how-to-clean question threads anyway (this drive me insane).
However, A new collector does not mean that they know zilch about what they are doing. We don't all just don't dump every chartuse-haired, so-soft, princess symbol, twinkle eye, mimic, nirvana, what have you in a boiling pot of oxyclean and dance around it horns blaring in anticipation like the pot is a minty pony factory.
Research is your friend, as well as trial and error (on baits first of course). Get a pony that needs cleaning? Look up how to clean that kind of pony first.
There are lots of sites that exist which give tutorials!
It does get out really really deeply ingrained dirt though. Which is honestly one of it's best uses. I've had a few brown looking ponies that turned nearly white after oxyclean. They were just covered with dirt and I thought it was just discoloration. I've had other ponies covered is some sort of nasty muck, and they were pristine underneath. Otherwise, I would have been rubbing off blush and symbols with acetone, or left brown around their cheeks and rumps. This is why people suggest it.
It pulls that stuff right out. It CAN be a miracle worker, but if used on the wrong pony, it can ruin it.
It's always just safe to work up in strength before jumping to the strongest stuff first. n_n