Wipe with a damp cloth. Dry completely.

Using your 6-inch knife, spread joint compound over the tape. Press hard enough to force mud through the mesh holes. Scrape off excess. Let dry 24 hours.

Cut a piece of self-adhesive mesh tape long enough to cover the crack plus 1 inch on each end. Stick it directly over the groove. Do not use paper tape here; paper tape will bubble over a vertical seam.