I have bought three NOS Old
Spice mugs with original soap in the last few years. I'm using one, removed the soap and kept it as back-up for another, and gave one to my son-in-law who uses it frequently.
I'm old enough that I bought several of them new when they were in production.
I see no benefit to keeping it and allowing it to deteriate or end up in the hands of someone that won't appreciate it.