  Since all couplings of the exotic $\Theta^+$ baryon to normal hadrons seem to
be small it is hard to reveal it in standard resonance searching. We suggest to
look for the $\Theta^+$ production in interference with a known resonance
yielding the same final state but having a high production rate. The
interference process is linear in the $\Theta^+$ couplings whereas the
non-interference process is quadratic. That gives an obvious gain if the
couplings are small. Moreover, employing the peculiar oscillating nature of the
interference processes one can reduce considerably the parasitic background and
determine the $\Theta^+$ resonance parameters.
