General Information :
Bare concrete floors are actually very porous. Oil, grease and dirt will permanently stain concrete if not cleaned off soon enough.
Tools & Technique :
Heavy duty degreaser/cleaners will generally do a good job keeping up the concretes appearance. Use according to directions.
Try to give the chemical time to work scrubbing may be necessary. Rinse off with water.
Sealed concrete must be treated more carefully. Harsh cleaners such as T.S.P. can damage the seal. Try a milder cleaner to start. Since the floor is sealed it will clean-up much easier than bare concrete.
Try to avoid messy clean-ups by putting cardboard under a oil-drip or lawnmower. Frequent sweeping gets rid of surface dirt before it has a chance to grind into the concrete.
Specialized Tools & Chemicals :
When possible pressure washing is an effective cleaning method for concrete. Be careful on older concrete too much pressure can break it apart.