throw them out or let them decompose in your garden the snails aren't coming back for them...LOL
The snails died and that is what is left you don't want the snails anyway they chew up everything
I would dig it up the best I could and take all the mess to your recycling center, don't worry they have seen it all before we did something like this with motor oil. Took yard rocks and all in 5 gallon buckets all they said was "whats in it?" & "Thank you" Don't make it worse with more...