Take your garden shears to them, clip out all the old outer leaves,runner strings and any excessive plants, old straw and blown leaves. Weed as you go. Leave the crowns and new foliage if any (mine have not woken up yet!) Top dress with poultry pellets and watch them revive. Suggest you harvest new runners this year into pots and start a new bed for next year. Its a fair idea to add two rows on one edge while scrapping two rows on the other edge, slowly rotating your strawberry bed across your plot.This gives scope to increase the amount or add new varieties to extend their season.