  In a complete metric space that is equipped with a doubling measure and
supports a Poincar\'e inequality, we study strict subsets, i.e. sets whose
variational capacity with respect to a larger reference set is finite, in the
case $p=1$. Relying on the concept of fine topology, we give a characterization
of those strict subsets that are also sets of finite perimeter, and then we
apply this to the study of condensers as well as BV capacities. We also apply
the theory to prove a pointwise approximation result for functions of bounded
variation.
