A good friend of mine is an exterminator, he said the green blocks do have a coagulant, one nibble and they soon die, 99% make it outside. We've used them for years & they work *FAST*, no guessing, no on going war. I own / manage rental properties as well, some out in the country. Every fall, the mice try to come in from the cold and I get calls about them. Once I put the blocks out, within a day or two there is no more evidence (black rice), 99% time no smell. The few times there was a smell, it lasted no more than a week. Tenants would rather deal with a smell for a week than being over run by mice. Even in my TT I leave them out, there will never be an infestation in there. I've seen these blocks work like I claim for over 25 years, like magic.