Sadly, cash isn't all that anonymous these days, as the serial numbers are all scanned on any large deposit or withdrawal.
It depends on with whom one spends it.
I can think of a half-dozen kinds of businesses off the top of my head that will buy and sell in actual cash. Places like pawn shops, auto wrecking yards, and other businesses that often cater to poorer people or deal in particular kinds of transactions. If one deals with these kinds of businesses then it's unlikely that cash will be easily traced as it'll go through a lot of hands as those business owners also spend money.
The opossum is a very sophisticated animal. It doesn't even get up until 5 or 6 PM.