Vinyl flooring, while fairly easy to maintain and clean, is prone to scratches. Small bits of gravel or pebbles tracked in from outdoors scar the vinyl surface. The damaged areas collect dirt, making them more noticeable. On sheet vinyl in particular, popping out bad tile and replacing it with a fresh one isn't an option. Rather than letting minor scratches become darker or more obvious. repair them with a clear liquid seam sealer.
Open all the windows in the room and turn on a ceiling fan, if there is one, to ventilate the area.
Dab some lacquer thinner onto a soft rag while wearing rubber gloves. Wipe down the damaged area thoroughly with the lacquer thinner to clean it and remove residue that may prevent the seam sealer from adhering properly. Allow the area to dry completely.
Place strips of masking tape closely around the scratch to avoid getting seam sealer beyond where it is needed.
Pour some of the liquid seam sealer into the applicator bottle packaged with it, if it is not already in such a bottle. Squirt a small bead of seam sealer over the scratch and allow it to dry completely.
Remove the masking tape.