How does Amazon handle returned products?

A lot of products sold by Amazon are free returns, or at least they can be returned easily for any reason. However, does anyone know how Amazon would handle the returned products? Will they just resell to another customer again quickly without any serious check or will they unbox the package of the item and carefully inspect the contents inside?

I am not so worried about returned food or anything too personal, I believe that Amazon will just throw them into the rubbish bin. However, for products of higher value and aren't for eat, I don't think they will just throw them away, but will they seriously inspect the items before selling to another customer again??