The ornamental design for an iron shaped grillbrush, as shown and described.
FIG. 1 is a top isometric view of an iron shaped grill brush in accordance with the new design;
FIG. 2 is a bottom view thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a rear view thereof;
FIG. 5 is a top view thereof; and,
FIG. 6 is a side view thereof.
The broken lines showing bristles illustrate a portion of the brush and all of the other broken lines are understood to illustrate the environment in which the article embodying the design is used. None of the broken lines form part of the claimed design.