might be a minor infection too. moldy buds can cause light-severe probs with many people but i've never heard of short-term use of foil screens/pipes causing probs. i always 'cook' my aluminum on the rare times they come in handy by burning off the surface of the foil before use (you can actually see the foil smoke from whatever oils and impurities are burned off) then always face the dull side out...iow, bud lays on the dull side. cooking too. i always put the food (usually used only for baked taters) against the dull side