I am not sure cockroaches are the right insect because they are particularly filthy, eating their own poop and all.
However a few years ago a friend of mine remarked how useful ants would be for such a role, for cleaning the floor of crumbs.
I think if you could find a way to borgify insects the profitable sector would be in agriculture.
Sell dragonflies and mantises programmed so seek out and destroy corn pests. Sell engineered grasshoppers who leave the corn alone but eat everything else.