My brother and his friends borrowed my tackle box and stored fish in it. Now the tackle box smells horrible. What would be the best way to clean it? Could I just hose it down and let it dry outside?

Use an ammonia-based solution with lemon and some warm water and clean it, then leave it outside to dry.

2 Tablespoons of baking soda per 1 quartz of water, and let it sit for 20-25 minutes. Then take it outside to get it dry in the sunlight.

I'd say your brother and/or his friends owe you $50 or so.  Either that or you've learned a valuable lesson about loaning fishing tackle to your brother and his friends.   Over the years, I have accumulated a back log of tackle that I consider "borrowers gear", i.e. gear that I don't mind lending out, and you find out about your buddies character depending on the shape it comes back in.

 

That being said, I would never, ever, lend out any rod or reel that has currently made the traveling team and is stored in my fishing truck.  Never, ever, may be harsh, but I haven't encountered the situation where I would consider it.

I agree with Fishes in trees, your brother owes you a new tackle bag and what ever other gear him and his buddies messed up.

 

I also agree fishing gear is personal stuff and I don't normally loan it out. If I'm on the trip too that is a different matter.

My brother and his friends borrowed my tackle box and stored fish in it. Now the tackle box smells horrible. 

Don't forget to slap him in the back of the head.