It's been a while since I've put one together so some of this may be a little off...

1: Look up from the rear dropouts towards your rear brake. there should be a little set-screw in the crotch of the seatstay junction. Remove that with (I believe) a 5mm allen wrench.

2: Remove your rear brake

3: Again, looking up towards the brake hole from the dropouts, you'll see a metal shaft running up the monostay into the elastomer. That needs to get removed. The easiest way to remove this is to thread a bolt into it (it'll thread into where you removed that set-screw) and pull. They can be a rather tight fit. I believe the thread is M8x1.

4: The elastomer can now be removed. You may have to spread the frame apart a bit to remove it.

I reckon you could use a standard citrus-type degreaser on the elastomer to clean it. You shouldn't have to lube anything. I do sometimes lightly grease the shaft (that you removed in step 3) to assist in going in, but it's certainly not required.