We investigate non-locality distillation using measures of non-locality based
on the Elitzur-Popescu-Rohrlich decomposition. For a certain number of copies
of a given non-local correlation, we define two quantities of interest: (i) the
non-local cost, and (ii) the distillable non-locality. We find that there exist
correlations whose distillable non-locality is strictly smaller than their
non-local cost. Thus non-locality displays a form of irreversibility which we
term bound non-locality. Finally we show that non-local distillability can be
activated.Comment: 4 pages, 1 figur