I assume you talk of a typical glass bulb style pipe? like one of these at the bottom of my post?

If so, then you shouldnt be adding any ash or herb in there, just drop the spice in there and heat it up slowly. When I used one of em pipes, I found that a torch lighter was much moar effective at heating up the spice, you have so much moar control over the heat. bic lighters will often burn the spice with one of em bulbs.