drywall duster
Basically, a drywall-duster is another name for a Mexican immigrant to Canada or America. This comes from the popular belief that Mexican immigrants will work for low prices so, hypothetically, one could pay a "drywall duster" 3 pesos a day to renovate his or her house. Thus they would be dusting off drywall while their employer threatened them with immigration offices and cobras.
"I paid a private contractor 6 million dollars to renovate my house" " Ya, I just hired a bunch of drywall dusters."