After a quick internet search, I found some great vintage clock faces on creatingmyselfcreatively.
Then, after a somewhat longer search through the scattered cache of craft supplies and collectibles that clutter my basement, I found a stash of rusty mini tart pans and jar lids to use as frames.
I printed out the clock faces in sizes that matched the frames.
My favorite frame is the lid with the wire grid over it. It reminds me of the (literally) old-school gym clocks that had cages over their faces to protect the glass from wayward basketballs.
I Mod Podged the clock faces onto the frames.
I “aged” the clock faces with some watered down brown paint and some old coffee grounds.
Then I put the clocks, a few silver and gold ornaments and some genuine faux snow into the shadow box. Unfortunately, the faux snow looked more like coconut flakes than snowflakes …
… so I swapped it out for some epsom salt, which makes much prettier (and more realistic looking) snow.