that's actually why i switched to paperclay, SS is so hard to sand and time consuming to sand. I don't have much advice other than this: Put the piece on the table when you sand, don't hold it up in the air. If you need to cushion it to keep it from getting broken, put a folded towel down first. Use sanding screens intended for plaster, they don't get gummed up as fast as regular sand paper. Use a sanding sponge or a sanding block with a high grit. Get a wire brush for cleaning files and run your sandpaper over it when the sandpaper gets gummed up. It'll dull the sandpaper faster- but you'll still be able to use it longer. Start with high grit, like 80 and work your way down. It's time consuming, but you'll get a better result. I'd also use gray super sculpey and not the flesh toned since the flesh toned is slightly transparent, so it's hard to see the uneven spots.

Once you get to a lower grit, like 220, you can switch to wet/dry sand paper. Get a bowl of water and dip your piece into it and sand. The water washes away the crap and keeps your sand paper fresher longer and gives you a cleaner sanding.
Sand in circles, not in one direction, this will prevent you from gouging your piece.

hope that helps!

thank you!

You're very welcome!