There are different levels of this, depending on what kind of smoker you are.

If you're smoking for pleasure, and can afford to toss 1/4 of a bowl left, you shouldn't stop when you don't see more green, but stop when the ash begins to turn from deep black to light grey, and you'll get a slightly harsher taste of smoke.

If you're trying to get every last bit, but no res, you hit past the more charred taste of burning ganj, until you get no smoke.

If you're trying to get every last bit INCLUDING res, hold the lighter on the bowl for a more extended period of time, and you'll get the harshest (but still psychoactive) smoke until the res is burned up.
Purple Banana Reviewed by Purple Banana on . Ash? A slightly noobish question, but after how long should i just toss the ash in a bowl away? Im asking because i keep on smoking from a bowl till theres nothing left, but i cant imagine that smoking ash is particularly potent or good for you? So should i finish the bowl as soon as theres no greenery left? Or consume it to the last molecule? Thanks for any info. Rating: 5