SB 11.17.49
sudra-vrttim bhajed vaisyah
sudrah karu-kata-kriyam
krcchran mukto na garhyena
vrttim lipseta karmana
Translation:
A vaisya, or mercantile man, who cannot maintain himself may adopt the occupation of a sudra, and a sudra who cannot find a master can engage in simple activities like making baskets and mats of straw. However, all members of society who have adopted inferior occupations in emergency situations must give up those substitute occupations when the difficulties have passed.