OK - cases & rocker boxes back from being stove enamelled

Head is away getting same treatment and should be back next week.

What do you think??  

  Before I go any further I need to clean out both crank cases and get into the oil ways and be confident that all the c**p is out of there. No point in putting the crank in if it's full of gunk is there?

I have considered getting a compressor so I can blast air through all the nooks and crannies.

Does anyone have any decent suggestions for getting their cases clean internally?