(US5492139-A)      Apparatus for using a cleaning fluid to remove a contaminating material from a combination material containing said contaminating material and a reusable material, said apparatus comprising:    a tank having a plurality of side walls and a bottom wall enclosing a cleaning chamber for containing said cleaning fluid;    a skimming opening in one of said side walls positioned a first distance above said bottom wall and providing fluid communication from within said cleaning chamber to outside said cleaning chamber;    a fluid circulation manifold positioned adjacent said bottom wall of said tank within said cleaning chamber, said manifold having a plurality of spray openings therein for introducing fluid into said cleaning chamber;    a fluid outlet opening in at least one of said side walls and bottom wall positioned below said skimming opening so as to define a recirculating drain opening in said cleaning chamber;    a recirculation pump having an inlet fluidly connected to said recirculating drain opening;    a conduit system connecting said recirculating drain opening and said fluid circulation manifold to said recirculation pump whereby said pump will cause said cleaning fluid within said tank to be circulated from said outlet opening to said pump and from said pump to said manifold where said fluid is recirculated into said cleaning chamber through said spray holes in said manifold;    a contaminant container outside said fluid chamber and in fluid communication with said fluid chamber only at said skimming opening for receiving said contaminating material exiting from said skimming opening, said contaminant container having a contaminant drain opening therein positioned below said skimming opening for discharging contaminating material without remixing said contaminating material with said cleaning fluid from said recirculation pump.    (US5589004-A)      A method for removing a contaminating material from a combination material contg. the contaminating material and a reusable material, the method comprising: placing the combination material in a tank having a cleaning fluid in it capable of sepg. the contaminating material from the reusable material; the cleaning fluid contg. oxygen consuming microorganisms capable of also consuming at least a portion of the contaminating material; circulating oxygen through the cleaning fluid so as to provide oxygen for consumption by the microorganisms; circulating the cleaning fluid around the combination material within the tank whereby the cleaning fluid will cause the contaminating material to separate from the reusable material and will cause at least some portion of the contaminating material to float on the top surface of the cleaning fluid within the tank; drawing off the contaminating material which is floating on the top surface of the cleaning fluid and removing it from the tank through a skinning opening in the tank; recirculating the cleaning fluid through the tank through an outlet opening in it which is remote from and lower than the skimming opening.    (US5772782-A)      A contaminant is removed from a contaminated reusable material (92) by placing the contaminated material (92) into a tank (12) and circulating a cleaning fluid (112) around it so that contaminant is sepd. out and floats to the top (114) of the cleaning fluid (112). Floating contaminant is then drawn off (32) and removed from the tank (12).    Also claimed is a tank for removing contaminants, which has a skimming operation in one of its walls, a fluid-circulation manifold and pump, and a contaminant container connected to the skimming opening.    USE -   Removing hydrocarbon contaminates from e.g. mats, rubber beads, air filters and oil filters.    ADVANTAGE -   Cleaning agents are used more effectively. The appts. is efficient, durable and economical to mfr.