Clear[red]
red[l_]:=Module[{v={},i,t,j},
  Print["Length[l]	",Length[l]];
  For[i=1,i<=Length[l],++i,(
    t=l[[i]];
    For[j=1,j<=Length[v],++j,t=Expand[t-v[[j]]*Coefficient[t,Last[v[[j]]]]]];
    If[!(t===0),(t=Expand[t/(Last[t] /. {OY[___]->1, ON[___]->1})])];
    If[!(t===0),AppendTo[v,t]];
  )];
  Print["Length[v]	",Length[v]];
  Print["Last /@ v	",Last /@ v];
  v
]