  The nanometer-scale gap inhomogeneity revealed by recent STM images of BSCCO
surface suggests that the ``gap coherence length'' is of that order. Thus a
robust pairing gap can develop despite the poorly screened Coulomb interaction.
This can be taken as an evidence that the pairing in high $T_c$ materials
occurs primarily in the neutral (spin) sector. We provide theoretical support
for this point of view.
