I know most of you already do something similar or know this, but for those that don't, just thought I'd mention it.
I always sand both sides of my wood pieces - puzzles, hangers, portraits etc.
When I cut out some puzzles however, the pieces can be quite delicate, small and easily broken if I'm not careful (see a few of my past posts LOL).
What I do to avoid that now is, I cut out the profile of the puzzle and retain the outer cut. I try to keep it as a single piece, but if not I will glue it back together - I call this profiling.
Once I have all the puzzle pieces cut out, I place them back into the outer cut (the profile) and sand the whole thing as if it were a single slab just as it was before I cut it out.
The pieces stay together very nicely, there is very little if any breakage ever and I can get the fuzzies out of the back very easily.
Just thought I'd share that