OP addresses this. Very little of what goes into those boxes gets sold as-is. Some more gets sold as rags, chopped up for insulation and pillows etc. Most ends

OP addresses this. Very little of what goes into those boxes gets sold as-is. Some more gets sold as rags, chopped up for insulation and pillows etc. Most ends up in landfills. The boxes are convenient, but don't really solve the waste problem. They just change who profits from the very small residual value in old clothes, and often not for the better. You're better off selling the very few best pieces (e.g. still-fashionable dress clothes in near mint condition) locally and donating the proceeds to a real charity. The rest will go in the trash anyway so might as well skip the middleman and put it there yourself.