The ChIP protocol I'm following has a low salt, high salt, LiCl and 1X TE washes, respectively.The low salt wash buffer has 150mM of NaCl, the high salt wash buffer has 500mM of NaCl and LiCl wash buffer has 0.25M of LiCl. I was wondering what exactly is going on chemically during these washes? How does the size of the metal ions assist with the washes and obtaining IP-ed chromatin? I use sepharose Protein A/G beads for my ChIP assays.