Attain soap recipe from appropriate source and make soap for your worst enemy. A discreetly hidden razorblade or fine glass particles should do the trick.
For a non-damage soap, try inserting a small dead sparrow - (these can often be found along roadsides). Imagine the look on their face upon finding (after a few uses) they are rubbing a dead bird on their face.
Try experimenting with all sorts of odd/foul things you can find about the neighbourhood!-- benfrost, Jun 12 2001 Lush Bath Stuff http://www.lush.co.uk/I bought my boyfriend some abrasive soap here and he didn't know whether to be offended or not. [lewisgirl, Jun 12 2001] baked, with razor blades http://www.hunwicks...%20the%20Gorgon.htmin this 1992 Peter Shaffer play [pertinax, Aug 03 2008] I like Peter, he's always so law-abiding. I am not so keen on benfrost, and I hope I never meet him in person. I don't mean to be rude but: Evil Soap plus the entire genital food category, Public Vomit Chamber, and the laziness of a wheelchair for home and office. Dear God. And I'm not keen on modern art anyway. For interesting soaps, try a company called Lush.-- lewisgirl, Jun 12 2001 rods: evil shampoo = nair-- mihali, Jun 12 2001 damn! I was hoping lewisgirl would be keen on me . ..-- benfrost, Jun 13 2001 Vintage BF, and a reference to an old PeterSealy post, I gather. What happened to that guy? I am not big on the glass (so declasse) but like the sparrow. A mouse might be softer. Or the snout of a pig?-- bungston, Sep 21 2005 random, halfbakery