or a coring effect of milling the exterior of a downhole tool without the center those skilled in the art will appreciate that the improvements to the debris catching tool using the modular designs makes them more likely to come apart at the surface for cleaning when laden with cuttings that could be compacted a plugged cleanout 100 allows an initial attempt to flush the cuttings clear of a surrounding modular housing before undoing the set screws 98 to allow removal with a pull out force at the opposite end such as near the centralizers 96 the modular design can incorporate a flow path with a debris receptacle in each module and a sinuous path for flow coupled with sudden enlargements of the flow area where the bends are so that the reduced velocity will act with gravity to allow the debris to drop straight down to an aligned debris receptacle in a given module below alternatively using modules as shown in fig6 the flow can come straight up through the modules and due to gaps between the modules where the velocity slows debris can still fall away and be pushed to the periphery when it will fall down into the annular collection area in part made possible by centralizers 96 around the tube 86 when there is no circulation the flappers 92 close and drainage to the mill 50 can occur through the.