I have used micro fiber unscented dusting pads for SHB control. It hasn't caught on yet around here but I believe they have microfiber pads in the new Dadant catalog under SHB control which does the same thing.
My routine for a hive inspection that has SHB's is to open the hive, check the Beetle Blaster traps, kill any that I spot crawling around then put a 1/2 duster sheet in opposite corners of the top box. After that I fill the tray with soapy water and come back one or two days later to check and clean the tray. If there are only a few dead SHB's I won't refill the tray. If there are a lot I keep checking and refilling till the number drop. After a week or ten days the duster pads get checked and replaced. I don't like leaving them in any longer, the bees will cover them with propolus which defeats their purpose.
Don't know if my routine would work for a larger beeyard, I only have three hives right now and they are easy to get to behind the shop. Keeping a hive strong is one of the best SHB controls, they are opportunistic and wait for the hive to weaken.