Throw them in jail until the property is cleaned up.  They will come up with a solution then.  This type of thing in Anchorage is so bad with people having 6 or more vehicles parked everywhere in their front yards and more in their back yards, every other house in my neighborhood has broken down vehicles everywhere on people's property and nothing happens.  I never experienced this type of problem until I moved here and now with the exploding crime epidemic and the economy going South, it's time to get out.  People have this false belief about what Alaska is like until they visit and see the truth.