While it is unlikely that there will be insects on the shelving, I suppose it's possible that the crawlers could be stranded when you treat the plants, but wiping with any decent surfactant - even Windex - should probably be fine.
Mealy bugs crawl far away to lay eggs, or to move to different plants. It can be difficult to find them. Scale adults, once attached to a plant, no longer move. Their eggs are kept under the mother's shell, where they hatch. The nymphs crawl away but generally stay on the plant.
__________________ May the bridges I've burned light my way.