Question about selling gold

I buy from estate sales and every now and then I find a piece that is gold. 14k, 18k... the iteams that are broken I've taken to a business that pays scrap prices for it. But I have now collected several that are pretty decent pieces that I dont want to just get scrap prices for. Does anyone have any advice? There is always someone who pops in my auctions and asks if I have gold. I always say no because i dont know who would be trustworthy to sell gold to on Whatnot. Does anyone have any advice about what I should do to get the most out of these pieces? Thank you for any help.