Cut out and replace
Are you tired of looking at that wine stain your brother-in-law so graciously gifted you last Christmas? Before replacing the carpet in the entire room, first try a cookie cutter repair kit. They’re available online (search for “cookie cutter carpet tool”) and at flooring supply stores. The idea is to cut out the stain from the highly visible area and replace it with a patch from a remnant, a closet or from under the sofa.
An adhesive pad holds the new piece in place. Some adhesive pads require ironing. For a stronger bond, use carpet seam sealer around the perimeter to fuse the backing of the patch to the backing of the surrounding carpet. You can buy seam sealer at home centers.
The kit we tried came with thorough instructions, but here are a few things to keep in mind: You’ll need to cut out the stained portion first so you can cut out a replacement piece with an identical pattern. Even if your carpet appears to have no pattern, it does. Before installing the new piece, examine the backing on the carpet. It should look like a grid of sorts (you may have to lift it up a bit). The orientation of the grid on the patch should line up with the surrounding carpet.
Try to clear a path for the cutting knives. The fewer carpet fibers you cut, the better. This is harder to do with looped-pile carpeting like Berber. If you’re lucky enough to have a remnant, try a practice run on that. As with most seams in carpeting, it might take a while for the patch to blend in, but it will be less noticeable than the eye-grabbing merlot stain.