Gmax: Remove a texture map?

Looked thru the manual to no avail.How do you remove a texture map from a channel such that thefile name is no long visible on the button/slot you click onto initally select an image?I applied one to the wrong channel and now MDL export barksabout a map on the wrong channel even when the check box forthe channel is unchecked. By channels, I'm talking aboutopacity, specular, diffuse, etc. in the Maps rollout of amaterial.