Patches > Remove is a set of functions that remove things from the active Shape object, usually so you can start over with patch layout.
Patches > Remove > Degenerate Corners. A “corner” is the intersection of two or more black patch lines. A degenerate corner is the intersection of exactly two black patch lines, also known as a “Degree 2” corner. This functions eliminates every pair of black patch lines that intersect in this way.
Patches > Remove > Patches removes all patches except contour patches.
(applicable when “contour patches” have been created around extendable (yellow) contour lines) - converts contour patches to regular patches. More specifically, it converts extendable (yellow) contour lines to plain orange panel lines, removes information about the width (“factor”) and length (“subdivision”) of the contour patches, and converts the contour patches to regular patches. The overall effect is that areas of high curvature are no longer treated specially, and NURBS > Fit Surfaces no longer has the ability to treat areas of high curvature any differently from the rest of the surface.
(applicable after Contours > Draw Patch Layout) - makes an orange contour line incapable of being converted to an extendable (yellow) contour line.