Here are MA's labeling rules. Notably... So here are the federal rules that apply to (most) growler sales: MA's labeling rules are quite clear: you must obey all federal rules, and you may not "use" or "traffic" container that bear or formerly bore the mark of a licensee. Therefore, MA brewers should willingly fill unbranded growlers. Additionally, MA brewers could go a step further to help their customers by signing a mutual agreement that consents to their growlers being used by other MA brewers that are party to that agreement. Boom--problem solved. Buy one MA growler and it's good at all MA breweries. So come on MA brewers--help out your fans and stop making us buy growlers from every brewery!