I agree with the others here.  Put the smack down.  My brother was around long enough to leave his caked on dirty dishes all over the counter and it made me mad.  I have three boys (so far) and I'm hoping I'll be able to give them some good helpful habits.  They make such huge messes!

Along the lines of what Hemidakota said, you're not teaching them anything be letting allowing that behavior. At their ages they need to learn a thing or two. I understand how hard that would be considering how they might react. You don't want to seem like an unloving parent, but trust me, taking a stand is the best thing you can do for them at this point. Just based on what you described. Good luck! :)

I agree. If they cannot follow the rules of the house, then they can get their own place.

hand  them a  lease  and if they  dont  pay  change  the locks!!!  They are old enough to know  better and they should treat  you wiht more respect.  Even my 13 yr old and 16 yr old  clean  and  help  with  cooking.

They need to pay rent, clean up, or get out. If they both have jobs they can get a pad together and treat IT however they want.

Kick the lazy kids to the curb or start charging them rent. That's what my parents did.

You have every right to make known your household bi-lawws. If they are not willing to abide by that, then do it. Perhaps, they may learn something about life versus receiving handouts.
HD