The Clear function allows you to delete everything contained in the current selection. If nothing is selected, GIMP will clear everything in the current layer. If the layer has an alpha channel (transparency), the cleared area is made transparent  Without an alpha channel, the cleared selection is filled with the current background color. If you have made a selection and click clear, the selection will still remain once the clear function is completed. Unlike Cut, Clear does not put the contents into the GIMP clipboard. The current contents of the GIMP clipboard are unaffected.
Default Keyboard Shortcut: Ctrl-K
The color information of the selection is not destroyed, just made transparent. The anti-erase function of the Eraser tool can return the area to opaque.