Hey Roach,
As was mentioned you can try drying it out, but you don't want to dry it out too much, as the whole intent and real purpose for using cypress mulch, barring its appearance, is for increasing humidity to the environment within the cage. Too dry (mulch) will have quite the opposite effect and can cause another host of problems. Too wet, and that too, can lead to its own set of issues. Something in the range of 50-60% relative humidity if possible, is what you should be gunning for.
Get your self a barometer, from Radio shack, or some other online source to help you get some kind of an idea of what the relative humidity is to start, and give you a better picture of the range. Mind you, that these devices are not NIST calibrated, nor are they perfect, but at least give you something to go by. With time, you will come to know what works and what doesn't.
Also, if need be, you might want to consider drilling some holes into the sides of the cage if it is made of plastic, which I am sure it is.
-Angel 
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"Until we lose our self, there is no way of finding our self."
-Henry Miller.