Since we started, we have had metal hive stands with legs that will sit in tins of oil. The oil doesn't dry out like water does. We put flaps above the tins to prevent the bees falling in them at the front. I was concerned about the amount of bees in the tins at the back, but I have been told the old bees crawl in there to die. We did the same thing the other day when we extracted to stop the ants getting in the honey. There are some acrid smelling ants here that would ruin the whole batch. Of course we have to keep the grass down under the stand.
A long-time beek has about 20 hives at the back of our property. When he checked them a couple of days ago, he'd lost 3 hives to ants. He is used to coastal areas that don't have the same ant trouble. His stands don't support tins of oil. They put grease around the legs yesterday, but it is hot here and we think the grease will melt away pretty quickly. a while ago I saw ants in his hives, and the bees couldn't land properly. We only had coopex to put around the hives as an emergency measure, and the next day there was a pile of dead bees. Fortunately no hive loss then. We think before the ants died, they walked the coopex into the hive, so when the bees died another bee would cart them out and land in the coopex with the dead one and die also. Those powders and chemicals don't last long with the wind and rain.
I know some people tie an oily rag around the legs of the stands too.
All the best,