The ornamental design for a grinder for salt or pepper, as shown and described.
FIG. 1 is a perspective of a grinder for salt or pepper showing my new design;
FIG. 2 is a side view thereof;
FIG. 3 is a top view thereof;
FIG. 4 is a bottom view thereof, with the area shown in dashed lined not forming a part of the design;
FIG. 5 is a perspective view of a first modified embodiment thereof, the top view thereof being the same as in FIG. 3 and the bottom view thereof being the same as in FIG. 4; and,
FIG. 6 is a perspective view of a second modified embodiment thereof, the top view thereof being the same as in FIG. 3 and the bottom view thereof being the same as in FIG. 4.