bust a rusty

To be used for taking the worst of all dumps. The kind of discharge that is so toxic it is the most brutal metal dump of all time. Every time. So metal that the act of getting rid of such corroded metal waste could only be: to bust a rusty.

"What the hell did you do in my bathroom? It smells like you were burning trash and old batteries in here!"
"I should have warned you. I had to bust a rusty."

I stopped to use the bathroom at the gas station near my house because I had to bust a rusty.