MY EXPERIENCE, MOVE TO SUN AND PLACE AN OIL PAN IN A DSBB. TROUBLE,YES, BUT IN THE LONG SCHEME OF THINGS. It is well worth the trouble, My hives are almost SHB free, Some trapped swarms are still in the shade with an oil pan and I sometimes see 3-5 SHB but those in the sun and oil pan WE see no SHB. If oil is a problem use water with a drop or three of Dawn. Add Sodium hexa meta phosphate used in some hard water treatment, swimming pools and even foods. Add a little to the water and it reduces the surface tension and bugs sink rather than using surface tension to stay on top of the water. If you can't find SHMP, The active agent in Calgon is SHMP. I like water better but it evaporates in a few days in this weather. If you think and plan oil works for months, with NO mess.