is performed in order to minimize this risk current reversing tools are not adequate in many situations since they require either ct manipulation or pumping to return to a safe position a hazardous situation arises if these functions are lost during the job also presently known reversing tools can potentially allow hydrocarbons to flow up the ct to surface the hydrocarbons can only be detected when they reach surface and already present a potential well control situation given that safety is a primary concern and that there is considerable investment in existing equipment it would be an advance in the art if reverse well cleanouts could be performed using existing apparatus modified to increase safety and efficiency during the cleaning procedures with minimal interruption of other well operations this invention offers methods and apparatus for these purposes the american petroleum institute api requires that downhole tools be equipped with two barriers that independently prevent fluid from flowing back to surface through the ct these barriers usually take the form of check valves if fluid flows downhole the valves will open providing minimal interference if fluid starts to move uphole however the valves close to prevent flow referring now to the figures fig1 a and 1b illustrate schematically and not to scale cross sectional views of a prior art flapper check valve useful in the invention positioned in a ct illustrated in fig1 a.