This idea of mine is somewhere in the queue over at Parent Hacks, but it seems wise to share it now since we're officially rolling into summer, a/k/a Sticky Soda Can Season.
Pet peeve: you set out your bin of recyclables religiously every (in our case) Tuesday, recycle everything right down to the bottle caps, and inevitably there's one or two bits of plastic detritus stuck to the schmutz that accumulates at the bottom of the bin. Eeyeewwwwww.
Solution: set up an itty-bitty mini recycling bin for the kids. A small bucket is perfect. We use an old lobster-scraps bucket from the Barking Crab in Boston. The kids pitch the bottle caps and the other small items into that bucket while the rest of the items accumulate in the regular recycling bin. Come recycling day you dump the contents of the smaller bucket on top of what's in the regular recycling bin, and they're much less likely to stick to the bottom, on account of they're on top and stuff.
If you want to be persnickety about it you can dump the smaller bucket into one of the larger recyclable items, e.g. a coffee can or a plastic salad box.