One wonders were some of you dispose of your oil filters?
Those definitely do contain heavy metals.
I am not worried about derusting iron/steel being a hazmat issue, it's not as long as you neutralize the acid. If you are seriously concerned about the non-liquid residual, rig a filtration system to filter it out of the neutralized fluid.
They say there are no such thing as a stupid question. They say there is always the exception that proves the rule. Don't be the exception.
