Take your seeds out first, look at the outdoor growing section and plant em in a field somewhere in the hope they will grow, or sell them. They taste NASTY when there smoked, if your grinder is good then it will split them up and itll be harder to find them later, so take them out before you grind.

Stems: Up to you, most of the stems are really small so you can leave them in to get the most out of your weed because they contain some THC, but there a tad harsh, so you can just pick the bud off and grind that if you wish.

Maybe make a brew with your stems? look at the recipie section and search for stems.