How to handle run-down homes with negligent owners in our POA?

We live in a small POA in Florida with about 50 homes.  Most are well maintained other that two properties.  These two properties are a disaster; they both need painting and one home has junk all over the front yard and it creates an eyesore.  We have spoken to one owners and even offered to chip to pay for repairs and clean up to no avail.  What do folks do in a situations like this?  Its horrible to look at and it effects the values of all the homes in the POA.