wipe-out question

I am working on a drawing for a sewer extension. Where the stub-outs are the
client wants a line with a 1/2" circle attached so that the contractor can
put the as-built location in the circle. I have created all of the circles with
a line attached as blocks and placed them all. Now the client wants the circles
to be wiped out so there is nothing behind them. I have never used the wipe-out
command but it seems like this might be a good place to use it, however the
command asks you to select a polyline and since the circle is not a polyline it
does not recognize it, further the circle is part of a block so that makes
things even more complicated. Any advise on this issue would be appreciated.