  We discuss the problem of non abelian constrained systems and the origin of
appearance of non abelian algebras. We show that it is possible, in principle,
to change a non abelian system to an abelian one, at least locally. Our method
is based on solutions of the differential equations due to the algebra of first
class constraints. We suggest that multiplicative constraints should be
regularized at each step of calculation. Some examples on SO(3) and SO(4)
algebras are discussed. We show that they can be replaced by abelian
constraints.
