A simple way to clean corrosion from a twist drill bit is to let your power drill help you. While applying oil to the bit at its point of entry, drill repeatedly into a block of hardwood secured in a vise. Friction of the bit against the wood and abrasion of the wood chips will provide a scouring action to clean up the bit in a hurry.
To make a room appear taller, paint the ceiling the same color as the walls. This eliminates any break between the two and gives the illusion of height.