The ornamental design for a lintbrush, as shown and described.
FIG. 1 is an upper perspective view of the lint brush showing my design.
FIG. 2 is a front elevation view thereof,
FIG. 3 is a back elevation view thereof;
FIG. 4 is a side elevation view thereof;
FIG. 5 is an opposite side elevation view thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The crosshatching, which is understood to represent a conventional material and continue throughout the entire upper raised portion, is partially shown in FIGS. 1 and 6 and omitted in FIGS. 2-5 for ease of illustration.