Ratter wanted

The wife's wood pile so much prized by the birds is now harbouring two young rats who nick the food from under the brown jobs' beaks and scuttle back into the rain forest. 'Sweet' they may be but they are growing into nasty bog standard vermin at an alarming rate. But how to get rid of them? Rosie the No1 Cat is arthritic and past ratting, Boots, Swedish Fluff and Geordie- (Last two names indicate ownership rather than accurate nomenclature) from neighbouring premises are well honed killing machines but are really more interested in eating birds than rodents but no doubt would have a go taking out a couple of Goldfinches en route. Anyhow the wife has so terrorised them when they do venture onto the back patio that they would take some persuading to come back in an authorised capacity. I may have to borrow an air gun and lurk in the 'summer house' ( More of a Spring Hut)and pot them when they emerge from out of the forest. But the wife wants a clean kill. (Not a wing-shot, a brief prayer and a small axe as coup de grace) Why? Let them suffer I say but then I have to follow orders in such matters. Rubba't Al Bayt-Lord of the House (and by extension wood pile) as the Arabs put it

Any ideas, ideally on a £20 note, gratefully received  ¶ 10:48 AM