As I understand it, skutch is another name for Couch grass? If so, then in your lawn, it shouldn't be a problem if you're cutting often enough, it just gets mown along with all the other grasses present. If you have it in large clumps, and its bumpy, you can try digging those clumps out, levelling and reseeding the parts, but no weedkiller suitable for lawn grasses will kill couch grass, simply because its a grass too.