putting the antifreeze (propylene glycol or ethylene glycol) down the
toilet (or sink) will be sure it gets to the waste treatment plant instead
of being available for cats, dogs, condors, small children, etc to drink.

Glycols are an unsaturated molecule with a few easily broken bonds... in
the lab they fall apart in reactions... so i'd think that a fairly decent
bio-remediation pond/center will easily degrade/recycle the antifreeze.

Now mufflers? I think yard-art or sculpures is the way to go there.

Matthew Pollard          "Racing with the wind and flirting with death
Dept. Of Chemistry        So have a cup of coffee and catch your breath"
University of Idaho
www.uidaho.edu/~poll7356