A couple of years back I had bit of an issue with rats in the outbuilding. They took up residence between the pitched roof tiles and the sarking and caked everything in a grey muck that looked like, and was almost as hard as, concrete. I soon replaced the edible pipes and bits with impenetrable equivalents, but they ate whatever they could (wood soaked in oil seemed to be the fallback for them).
Then we got a cat, grew into a big ginger tom - not too bright but very handsome and (surprisingly for a cat) absolutely devoted to me. Can't pop the bonnet on the car without him joining me to inspect the engine. He's also an excellent hunter. I've not seen a rat since.
Now that we're moving house I've finally been forced to dismantle all the bio kit. I've dragging processor et al out into the garden. I've also treated myself to a powerful new pressure washer. Finally I can blast the caked on grey rat-cement off the pumps and pipes and bits. The paint on some of the pumps has come off too, but at least they're clean.
I also discovered that a pressure washer capable of removing paint is also capable of stripping insulation of a hot water cylinder, and, somewhat more painfully, skin off hands. Stopping a pipe flapping about while it was blasted seemed like a good idea at the time.
My brother has volunteered to have all the bio kit stored in his garden while we move. I'm not sure he realises what he's let himself in for
