I've done the lye thing before (outside, with full rubber suit and faceshield) and wouldn't really recommend it unless you've worked with chemicals before. It boggles my mind that I can walk into any store and buy lye and other crazy strong chemicals without any questions asked. I did mine outside in the winter to alleviate the heat issues a bit. I'd plug any holes from the bottom bracket and stick a funnel at the top of seat tube sealed up nicely with some caulking to try and keep the foaming lye off the frame.