hi Rob
I learned a trick for aging the brass tacks, from Chuck Burrows.
Get a metal pan, fill it with enough salt to cover the tack head, when you place them in upside down.Put all your tacks in the salt. Now take your little propane torch and heat the shafts if the tacks.
The affordable tacks here have steel shafts so this method anneals them and has the benefit of aging the heads. I am not sure if it would work on 100% brass tacks.
Knife and sheath look great!