the classic "acid dipping" was intended to remove metal. The "old wives tale" was that they left the object in the tank for a longer period of time to reduce the thickness. Actually, it was probably a more acidic solution. When we had the Landcruiser dunked, they were doing some ancient Ferrari aluminum block....
if it was a metal removal process, they wouldnt have risked the block.

Also, regarding leaching from seams, we havent seen any indication of anything such. We have taken a blow gun to the seams and in the sheet metal bracing and nothing comes out. The only thing that didnt come out was a couple of places where bondo was in the dent puller holes and that popped out with a knife.

For the plastic media, look at Randy's web page
http://www.hotrodscustomstuff.com/prostrip.html
that has some pics