I'm repotting part of my bulb collection now and, as usual, wondering about cleaning them. Just how much of the dead tissue should be removed from various kinds of bulbs? I generally remove anything that's loose enough to fall away with gentle pressure, without tearing at the living tissue. But I wonder how much the accumulation of old tunics and so on contributes to the health of the plant? Do multiple layers of tunic insulate the bulb? Or do they smother it and cause it to decline? What about the old tissue at the bases of some irid corms? Does the plant derive nutrition from its dead tissue from previous years, or is this debris simply a medium for fungi and bacteria? In nature, many layers of tissue would build up over the years, and I see some bulbous and cormous plants in the garden that I know haven't been significantly disturbed for 20 years or more but are still flowering well. Comments from experts welcome! Jane McGary Northwestern Oregon, USA