This job is a partial new retaining wall tieing into an older block wall. The new wall will be reinforced concrete this is not really the issue. The existing block wall is not that old, probably less than 5yrs, 8"x8"x16" block, and is in pretty good condition. The wall hieght is 4 to 5ft. The block wall is currently hollow and we were planning on grouting the cells and adding rebar. The problem that just came up is that when we peeked underneath the cap on top of the wall we found it is filled with broken bricks and soil We drilled some prob holes a the base of the wall too and found the same thing. I have some ideas, but does anyone have a proven meathod for cleaning out the cells?