Then, it hit me, Uranium Ore. I doubt that any of them had a can of this laying around the house.
It was a bit pricey, $39.95, but it was reduced down from $49.95, so, I saved $10 right there.
Uranium Ore samples are useful for testing Geiger Counters, and in checking further, they are License exempt.
I quietly checked around to see if any of my friends had Geiger Counters, and I was pleasantly surprised to find out that many of them did, so this sample of "low level" radioactive material would come in handy for them.
I called the post office and they concurred, that if the item is shipped in accordance with Postal Service activity limits, specified in Publication 52 and if the Radioactive minerals are for educational and scientific use only, and to test and calibrate their Geiger Counter, then the shipping was, in fact, legal.
I am including a little "Thank You" card with each gift, to be signed and returned, stating that the recipient of the gift had no intention of, well, making a bomb, or anything like that, just to be on the safe side. "Thanks for the gift, I will not use it in the preparation of making an explosive device of any kind."