  We propose a new "Hamiltonian inspired" covariant formula to define (without
harmful ambiguities) the superpotential and the physical charges associated to
a gauge symmetry. The criterion requires the variation of the Noether current
not to contain any derivative terms in $\partial_{\mu}\delta \f$.
  The examples of Yang-Mills (in its first order formulation) and 3-dimensional
Chern-Simons theories are revisited and the corresponding charge algebras (with
their central extensions in the Chern-Simons case) are computed in a
straightforward way.
  We then generalize the previous results to any (2n+1)-dimensional non-abelian
Chern-Simons theory for a particular choice of boundary conditions. We compute
explicitly the superpotential associated to the non-abelian gauge symmetry
which is nothing but the Chern-Simons Lagrangian in (2n-1) dimensions. The
corresponding charge algebra is also computed. However, no associated central
charge is found for $n \geq 2$.
  Finally, we treat the abelian p-form Chern-Simons theory in a similar way.
