go to heritageauctions.com.
I dealt with them several months ago and they were great. They were professional and did exactly what the said they’d do. Contact them, send them a picture and a description of what you have and they’ll send you a quote as to what they’d sell it for. If you want them to sell it, they will.
I had a letter from Robert Oppenheimer to my Father and it fetched $2400. They do sports as well.
Thanks, Hildy!