The ornamental design for a can cap, as shown and described.
FIG. 1 is a left front perspective view of a can cap showing my new design in an opened condition;
FIG. 2 is a left rear perspective view thereof;
FIG. 3 is a left side elevational view thereof, the right side elevational view being a mirror image;
FIG. 4 is a top plan view thereof in a closed condition;
FIG. 5 is a left side elevational view thereof in a closed condition, the right side elevational view being a mirror image;
FIG. 6 is an enlarged left side elevational view thereof similar to FIG. 5, the right side elevational view being a mirror image; and,
FIG. 7 is a enlarged left side elevational view thereof similar to FIG. 3, the right side elevational view being a mirror image.
The broken lines showing a can to which the can cap hereof may be attached are for purposes of illustrating environmental structure and form no part of the claimed design.