Any seed type things I usually put in 200 degree oven for few minutes-kills any bugs inside the acorns,do it with pinecones,any kind of seed pods,even old nuts that I'm going to spray paint. I used to make small wall plaques of natural things. Don't know how large they are but could get about 3 in round plaques from Michael's & stain & attach. I think hot glue would work for reattaching cap to acorn & for attaching to plaque. then spray the whole thing with clear acrylic. Date & name kind of tree or address where tree was on bottom. Could use as paperweight I guess. I have 2 3x5 long plaques hanging up in my house with dried acorns, a flower look hard pod from neighbor's tree, tiny pinecone looking things about 1/2- 3/4 in. long & couple of other things. They look like they are expensive but weren't. Used med. stain to match furniture in the room, fruitwood I think & sprayed the whole thing with clear acrylic. They look same as day I did them. I wipe the dried parts carefully with damp cloth,furniture polish on the wood. Hope this helps. Jan

A friend of mine is painting acorns to look like snowmen, she made necklaces out of them. Don't know anything about preserving them though.
B

Sunnyca thanks for your thoughts. This helps me. It is pretty crazy to try to something with one acorn isn't it?? Wish I could have gathered more. These are food for thought!!
Scat

Check out this blog. There are a few cute things with acorns that may give you an idea. I think a small ornament based on something like the necklace at the bottom of the page might be a nice way to display it. You could attach some sort of hangtag with a poem or rememberence on it.

Here is a link that might be useful: Acorns

After looking at size of most of those acorns Adellabedella listed site for, they are really small. I was thinking of large ones like some of trees out here have. The caps are about 2 in. across. If they are tiny sure won't fill up much space!! Maybe you could get a small glass domed stand & hang from little wire stand inside. Like dolls are sometimes placed in. Jan