http://e26whn2524322mkxb3cbyk27ev2ihhq2biz35hty7gzgsyrwrygq27yd.onion
This short post describes how to replace the valve on a stuck (or dripping) tap - the photos and examples are for a quarter turn tap, but the same process also applies to a twist tap (i.e. one that turns multiple times and uses a compression valve).