I do jugs here and it seems like some days we stop by the store morning and night depending. Most of the cartons come from the parents of infants who want their child to be on homogenized milk since I use 2% they must supply if they want. I ask for a carton to be brought and used as needed. Many of the families also used the cartons at home too since they used 2 or 1% themselves so they would bring me the cartons - assume they just rinsed or used soap only to wash so do the same bleach out. Spread the word at your church, or other social group you go to. A lot of seniors buy just cartons and would be more than glad to share. Take a walk on recycle day and find the families that have them in their bins - while in most cities you aren`t supposed to help yourself from the bins you would know which famililes to approach asking them to save them for you. The more cartons the merrier - entire forts can be built and so much cheaper and safer than the wooden hollow blocks they use in kindergarten.