Take a piece of regular cardboard rip the facing off exposing the waffles.
Place it on top of the top box frames with the waffle side down.
Go back in a few days later remove cardboard and look at all the SHB living in it.
Dump cardboard in a 5 gallon bucket with soap and water.
Also on linda's site is the SHB trap she uses it is also very good.http://beekeeperlinda.blogspot.com/2007/07/small-hive-beetle-trap-is-working.html