I've been using them since summer '08 with no adverse effects. I use plain, ordinary, natural soap bars--saponified oils with fragrance.
I've never seen soap bars with chelating agents, but that doesn't mean they don't exist. If you're interested in a product that contains EDTA, but is gentle, you may want to try CJ Daily Fix. If you want something stronger, Nexus Aloe Rid.
3a (Corkicelli), highlighted, fine, low porosity
modified CG, since April '07
CG since 3/11/08
HGs: Anything Sevi; Curly Kinks Satin Roots, Curlycue ReNew and Coil Jam; homemade FSG and okra gel; soap bars; UFD Curly Magic; Botanical Spirits Jellies, CJ Repair Me