Soaked mine in oil for a few hours before install, then while in the oil I used an old push rod and primed them "underwater", you could do the same with them in the block. As far as the big chunks of stuff I have a little vac that I use to suck up nastiness and it worked awesome, oven cleaner works great on that head at a carwash, really cleans it well, when putting the t stat cover back on use thread sealant on the bolts just to make sure you don't end up like this...

 

Pic

 

My small anoying oil leak turned into head gasket which turned into complete tear down of head to new valve guides, pushrods , lifters, head baked and decked, to new fuel injector o rings- welding the crack on my mani.....

 

Such is the life of a Jeep owner!

 

Lol it was my long arm money

 

So clean

 

2 hours later

 

All reinstalled Started right up, much more responcive