hi , if it was me personally i would use pellets( like softus suggested) , you could get the grain matching up to make the pellets blend in near perfectly, or at least use the odd nail as woody suggested ... bear in mind that the gripfill ( or pink grip which i prefer) only sticks to the outside finish of the wall , for example , if the wall is painted it will stick to the paint , so what happens if the wall gets damp??? answer ..the paint peels and the skirting comes away , ..its a modern quick way of fixing skirting ( on site we gripfill it and then fire a paslode nail in ) the pin is used to hold the skirting until the grippy goes off!! cheers les