cropping for print

Hi,

so i'm trying to send a file off to print.  they've requested an eps file as the pdf wasn't holding the colors true.  this is an enourmous wall mural (over 20 ft long) so it's an intensively large file.  there are 3 walls and the two side walls are quite small.  i made a clipping mask and adjusted the artboards for each wall, but the grpahics for the entire mural are still ghosting thru.  how do i crop these off on the smaller side walls so it's just the portion under the clipping mask that comes thru?