Reduce grubs in compost

These can literally grow to 2.5" long

I've had problems with big (thumb size) white grubs in my compost ever since I started composting 6 years ago.  I usually pick them out and pitch them against the block wall where they explode into gooey guts on impact.  I find great satisfaction in this, I hate them and feel nothing but pleasure when they die; I'm convinced they develop into Japanese Beetles and then swarm around my yard eating the leaves of my many trees.  Although it is fun to use the wiffle ball bat to hit them as they fly around!

3 pieces of cardboard to keep the
grubs out of the compost

I've been working on preventative measures lately and one trick that is working well is to line the bottom of the pile with cardboard.  This prevents the grubs that are in the dirt (there are many) from digging up into the compost.  I know they are still getting in from the sides but there isn't much I can do about that without making substantial changes to my design.  I think the best approach will be keeping it HOT and flipping a lot, basically just cook the little suckers.