I have SHB in my hive. They came free with the nuc I purchased, yay.
Following the advice of the people I bought it from, I have added blue (must be blue) non scented chux cloth over both sides of the hive and over the top of the frames. 3 whole sheets. I pulled at the sheets to fluff it up with small holes that the beetles can try and get through as the bees chase them around the hive. The beetles are getting trapped in the chux fibres (given they are spiky) and they die there. I’m not sure if this is already well known but it’s a cheap and effective method to catch some of the little buggers.
Make sure to tuck the chux under between the lid, box and base so the bees cannot try to remove the chux and potentially block the entrance of the hive which could cause them to overheat amongst other issues.
I also filled the bottom tray with used chip oil and that has 10 dead SHB’s in there after 1 week.
I was also able to find and squash a few when I opened the hive.
Best of luck with your hives