Each time you complete 0-2 (Pussy Galore), Voice removes ALL your transformations, not just cat-girl's (she won't do this if she is a cat-girl herself though). That level is easy and quick to complete. You can also save your pure human character in the hot springs (for 10? crystals, one-time pay) and then load it (for 5?). That is cheaper than cleanse every corruption separately.