Do any of the treasures need to be kept or should I sell them all? I'm talking about the beerstein, spinel, gem/jewels, etc. I have combined the headgear thing (forgot its name) with one jewel to make the price 10000. Is there a point to keep any of the treasures or just sell them?

Ok, sell all your Spinels and that "head gear" is called Elegant Mask. Combie every treasure that is combie-able with the items it can be combied with. Don't sell the Beersteem untill you'll combie it with all the gems (green, yellow and red). If you will examine treasures they'll tell you the following things (for example): "It looks like something may fit inside", "Like it was once set in something". Well I hope you know what to do from here...