The ornamental design for a self-sealing toothpaste cap, as shown and described.
FIG. 1 is a top perspective view of a self-sealing toothpaste cap according to the present invention, shown in a position of use attached to a tube of toothpaste drawn in broken lines and not claimed;
FIG. 2 is an exploded top perspective view thereof, showing the manner of assembly with an unclaimed tube of toothpaste;
FIG. 3 is a cross-sectional view taken in the direction of line 3-3 shown in FIG. 1;
FIG. 4 is another cross-sectional view thereof;
FIG. 5 is a bottom perspective view thereof;
FIG. 6 is a side view thereof;
FIG. 7 is a top view thereof
FIG. 8 is a bottom view thereof; and,
FIG. 9 is another perspective view of the design of FIG. 1 shown in a position of use attached to a tube of toothpaste in the hand of a user applying toothpaste to a toothbrush, which is all drawn in broken lines and not claimed.
The broken lines in the drawings illustrating a tube of toothpaste, a human hand, and a toothbrush all depict environment and form no part of the claimed design.