I made my own out of scraps of .032 and etched numbers into them. I've been using the same set for about 10 years now with no problems. Heck, half of mine have Akzo primer on them as well since I leave them on while priming. Doesn't seem to have a negative effect on the alumiprep or alodine, although that's just my experience. Their surface area in relation to the parts you're prepping is relatively small so I doubt their effect would be much.