The commands Ncopy and Clip and the FRAME variable work with Xrefs, but they also work with blocks. Ncopy works with blocks the same way as with an Xref: start the command, pick individual objects, press escape, or continue as if in the Copy command. If you Clip a block, you will see the frame if it is set to 1 or 2. Set it to 0 to have it disappear. When FRAME is set to 0, it will not display or plot the frame; 1 will display and plot the frame; 2 will display but not plot the frame. FRAME is a system variable that overrides all the various *FRAME system variables (see help for more information). Don’t forget you can pick on the frame and use the arrow to invert the clip area.
Notes from Cadalyst tip reviewer R.K. McSwain: As Kent points out, certain commands that are thought of as Xref commands also work with blocks. AutoCAD actually considers Xrefs as blocks with an external (as opposed to internal) source, so it stands to reason that these commands work with blocks. We also tested clipping a dynamic block, and it should be noted that dynamic block grip points that fall outside the clipped area are still accessible when you select the block.