TO: All melanoma researchers, doctors, and patients.

A famous 2002 study found that a small spot of gray duct tape applied to a wart for up to two months eliminated it in nearly all cases, whereas a recent 2007 study found that transparent duct tape hardly worked at all. The investigators jumped into the most complicated speculations, ranging from the body's immune system to the adhesive's magic chemicals, yet what is the simplest explanation for why the opaque version resolves warts but the clear one does not?

As sunburn vividly demonstrates, sunlight stimulates circulation in the skin, so darkness must dull it. By blocking light, the gray duct tape just reduces blood flow to the wart and it starves.

But a spot of pigmented tape is an artificial mole. Thus, tape occlusion should come with a warning--it raises the risk of melanoma.

James Semmel
Albuquerque, New Mexico