How to sell old Warhammer 40k in bulk

There are sites like The Troll Trader (trolltrader.com) whose business model is to buy second hand models and re-sell them.

They're UK based though, not sure about the practicalities of selling to them, or how choosy they are about what they purchase.

The norm would be to list what you have on Ebay or to join Facebook groups for buy/sell 40K and list your things there.

There are games where models really hold their value well. Warhammer 40K is a bit mixed, there can be a sweet spot where models are rare enough to have value, but the game has also scaled up and had older ranges replaced, my impression is very old models are becoming quite niche in terms of desirability.