OT,
If you have a Menard's, Lowe's or Home Depot nearby, they sell food grade buckets with their other non food buckets and some seals. Here, they are not expensive but a bit thin 5 ml I think.I also posted(thanks RJ) in an earlier post a site that sells buckets and the Gamma seals in "bulk" I didn't think it was expensive for good quality thicker buckets and seals.