Kill the bilge pump!
First off, pull the fuse on your bilge pump(s) so none of that stuff gets pumped overboard! Once that's done you can probaly scoop most of the stuff up with a small flexible cup (like a former yoghurt container. Now you're probably down to a small layer floating on whatever water was in your bilge and stuff soiling the bilge surfaces. You should be able to take care of the slick on the bige water with one of the oil absorbant products from any marine store (I think Practical Sailor did a review of these a year or so ago). Once you've done that, scrub the bilge surfaces clean with a detergent or bilge cleaner, rinse (you did disable you bilge pump, right?), and use a hand pump to pump the bilge into a bucket so that you can dispose of the liquid properly (not in a storm sewer or body of water). When you're happy that the bilge is clean, re-connect your bilge pump.
