Here is a recent print on American Apparel's BB401 50/50 in black aqua.  This was a five color discharge which ordinarily would not be recommended on a 50/50, but it worked for the look of this line was going for.  

Since discharge only works on cotton and not polyester, only half of the fabric in this shirt was dischargeable.  The end result is generally a very muted, "dirty" discharge look.