We claim the ornamental design for a can top, as shown and described.
FIG. 1 is a top perspective view of a can top according to a first embodiment of our new design.
FIG. 2 is a left side view thereof, the front, back, and right side views being identical to the left side view.
FIG. 3 is a top view thereof.
FIG. 4 is a bottom view thereof; and,
FIG. 5 is a left side view thereof with a section cut away to show that the claimed design has a smooth, non-ridged shape and that the crimpled appearance is surface indicia.