Collecting and selling scrap metal can be a lucrative business, but only if you know what you are doing. For the most part, dealers pay scrap metal collectors by weight. Therefore, the more waste metal you gather, the more money you fetch. Thus, most scrappers prefer to store their metals until the pile gets big enough to haul to a yard. However, things can get tricky because poor storage can degrade scrap metal quality, affecting the amount of money you get paid.