family - you gotta love them......

My 2 nephews ask if they could store some junk cars on my property, they had to get them moved, the landlord told them to and the junk cars would only be on my property for a 'short time'... A 'short time' to me is 6 months...Well 8 years has passed and after a big family fight they are gone. The boys were to work around my place to pay for storage fees. We are talking about 10-12 cars. The boys did nothing whatsoever. They gave me 2 junk cars to help pay storage but will not give me the titles, no title, no crushing of cars, so bottom line is I got nothing but fewer family members out of all this. Can I get storage fees out of them now. I think them disrespectful boys need a good lesson.... No contract was signed but the boys did tell the Deputy they gave me 2 cars for some storage. Wouldn't that be admitting they knew storage fees would be collected? My question is, do I have a leg to stand on in court? Thanks