My own advice to my daughter will be to sell my collections (stamps and cards) via an auction house that I'll recommend. She'll also have an indicative list of material to send them. The trick is finding the right auction house for the level of collection, and also the one that will put more effort in separating the material for lots. Commission will be about 20%. My understanding is that the commission rate for those who sell on behalf of others on eBay
is closer to 30-35%.