I claim the ornamental design for the magnetic sign sleeve, as shown and described.
FIG. 1 is a front view of the magnetic sign sleeve.
FIG. 2 is a rear view of the claimed design.
FIG. 3 is a left side view of the claimed design.
FIG. 4 is a top view of the claimed design.
FIG. 5 is a bottom view of the claimed design.
FIG. 6 is a perspective view of the claimed design in which an advertisement is partially inserted into a slot having closure means along a top edge; and,
FIG. 7 is a perspective view of the claimed design in use along a surface of a vehicle and with an advertisement fully inserted into the interior of the sleeve.
It shall be noted that the both the advertisement, letters forming the word “LOGO”, and said vehicle are all being depicted in broken lines, which is environmental matter forming no part of the claimed design.