How can I cheaply refresh parquet in an apartment?

How to make parquet look as before?

• I am renting an apartment, and I think I spoiled the parquet there. I put a pot with a flower right on the floor, and somehow the floor under the pot looks darker now: I think the water was coming through. Now there is a distinctive dark (wet?) circle on a very visible spot. Does anyone know how to get rid of it?

• Answer:

  You may be out of luck, water stains in wood are tough. Try a wood cleaner and scrub, scrub, scrub. It may at least lighten the stain. But don't scrub so hard that you remove the normal wood stain. It would look even worse...