Thanks for the suggestions all. I put all of the tackle in a bucket with some hot water and oxygen bleach over night, and the boxes themselves got submerged in garbage cans with hot water and something called Rockin' Green which is a natural laundry detergent that is intended specifically to deal with biological (ie sweat and BO) stains and odours. Rinsed it all off this morning and have had everything baking in the sun in the yard all day. Results seem promising - I think all the hootchies might still have a bit of a smell retained but the boxes themselves now seem fine as does any metal or hard plastic gear. I'll update again once I put everything back together and close them up for a while. If anyone is curious what gear was in the boxes, happy to post some pics - there are some antiques in there for sure! I'm not sure if the previous owner was fishing only for bottom fish or just hadn't used this stuff in a while or didn't follow the regs so well, but there isn't a pinched barb in the lot that I've seen so far!