Keith, "Skins" format is an alternative scoring system. A point skin is awarded for each end won, while the skin value increases for each end as the match progresses. 
Such an end is said to be won, if the player with the hammer has at least 2 stones counting, or the player without the hammer steals the end. 
If neither of these occur, the skin is carried over to the next end. 
The skin value for each end: 1 1 2 2 3 3 4 4 5 5.