How to catch a leprechaun

We try our best to catch a leprechaun every year and make a fun trap together. This year we made a trap and hope to trick one by having him break the rule on the sign (leprechauns like to break rules) and climb up the ladder to reach the shiny paper but, as he does he'll fall right through hole in the the lid and we'll CATCH him! At the very least, we're hoping that he wont make the water in our toilet green or leave green kiss marks on our faces or footprints in our kitchen! Those tricky leprechauns...