You'll know them by their stripped metal office furniture sitting out in front of their Chelsea shop. Green Kay Office Furniture sells reused office furniture. Some of our favorite pieces there are the old mundane steel file cabinets they've refurbished by sandblasting then clearcoating. The result is an industrial-looking silver metal cabinet with entirely new life.
We have a flat file with the same treatment but we did it ourselves, removing the industrial grade paint finish with stripper. It was no easy task and we'd definitely consider Greenkay's cabinets if we were to acquire more.
They also occasionally have very cool vintage drafting desks and wooden files for sale. Not cheap, by any means, but a good source for cool, refurbished office furniture.