I have two rat racks that use the mortar tubs from Home Depot with the nail hole in them. The way I constructed my rack with the wire mesh lying flat against the top of the tub, the rats don't have access to the nail hole and I have been using them for almost 6 months now. I went to Home Depot just the other day to pick up more tubs b/c I'm building another rack and they had the exact same mortar tubs WITHOUT the nail hole in them. I was shocked, b/c I had been thinking about the nail hole in them and the concerns people have using them and then all of a sudden there is no more nail hole!
But either way, I wouldn't worry about using them as long as they don't have access to the nail hole. It seems to me, that if you build the rack the way most people do, the wire mesh covers it and the rats can't get to it!
Hope that helps!
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Michael
