[en] Losses of fast charged particles from open traps with a sharp plasma-magnetic field boundary (β=1) through the plasma surface caused by the force lines withdrawal from this surface are considered. The proposed method allows calculating surface losses in magnetic traps without axial symmetry under the assumption that the longitudinal system dimension is much larger than its R transverse dimension and the Larmor radius rsub(B)<< R. The importance of elimination of surface losses in nonsymmetrical systems is confirmed by direct calculation of their value for concrete base- ball configuration where surface losses turn to be comparable with direct butt-end particle losses through the 2rsub(B) width slits. It is shown that without changing the direct butt-end losses values one can eliminate surface losses. It turns that the requirement of absence of local surface losses is incompatible with the MHD stability. At the same time MHD stable configurations exist without surface escape in the ''global'' sense