I have two derivations: 1. Originally the family came to Russia from Poland as refugees of some progrom. The Russians called them Polaks rather than their own family name. It somehow stuck. 2. The Scottish clan of Maxwell is involved. Outside of Glasgow is a river whose name I forget. The river had a stony bottom and there were large river stones in the river besides. Over the centuries the river or glaciers wore depressions in the river bed using the large stones as a sort of abrasive force. The result was that there were depressions in the stony river bed. The river was relatively shallow and in times of low water or drought as the river receeded the depressions still contained water. These water containing depressions are called in the Scottish dialect "pollocks" or "poluks" (I'm not sure of the spelling). People from the area were known as those "guys" from the Pollocks or Polucks or however it is spelled.
For example, the Maxwells of Pollocks; the Maxwells are the clan that sems to be the one in "control" of the area. There are a myriad of Pollocks in the Glasgow telephone directory. The name is all over the town. Quite a shock to a real Pollack. I thought I was a clan member, my father said we came from Scotland. His name is Maxwell George Pollack, his cousin is named George Maxwell Pollack. Quite an amazing coincidence. But since I can't prove my clan affiliation(no baptism certificate, etc.) the clan won't have me. It's their loss. I have the tartan tie, anyway.