I have the VP6 and although it is currently running on a Water Cooled setup now, I had Two Alpha PEP66s with the Deltas not too long ago.
You didn't tell me what your ambient temp or case temp is so that may also be a big factor in the temps you're seeing.
I have two P3 700s @ 1.0Ghz
I also have a modded Chenbro Net Server Case which helps case temps.
My Case Temps were and still are around 25C (MBM5)
My CPU Temps were and still are around 26 and 27 Idle
and at full load (Sandra Burn-in) for hours my max temps are around 33C.
Granted, I do not have the heat spreader that Intel put on your processors
but I am still using the thermal grease that came with my Alphas.
So, you should probably focus on Case airflow first if you have'nt already and then try re-seating your heat sinks. If that doesn't work, take a look at your fans. The Deltas I was using were great but I liked the noise so much that I have gone watercooled! I would try all that first before prying off the heat spreader. I know Ol'man has done it successfully several times but that would be my last option. I just don't have the money if I should happen to slip, or the ground shakes, or my son bumps me, or ........
Anyway, hope that helps