We don't have a huge variety of changing leaves yet, but we needed something to divert us from the rain, so we collected some to preserve in beeswax. I melted some beeswax candle stubs in a homemade double boiler (a large can from the recycling in a saucepan with a few inches of boiling water), dipped the leaves into the melted wax, and placed them carefully on parchment paper.
While the children napped, I strung them on some embroidery thread to make an autumn garland.
We'll be going on a little trip in a few weeks to my husband's seminary. Hopefully, there will be lots of leaves changing there so we can do this again!