anyone had their rear end housing powdercoated?

[brianz426]

 I had my 8-3/4 axle housing and end plates powder coated and they turned out great. My problem is getting the inside of the housing clean. They blasted and baked the housing and the inside looked clean and dry except for the dried grease/oil residue.
I started with an industrial water soluble machine shop type cleaner degreaser. I thoroughly washed the interior with a brush. After it dried I cleaned the inside again with brake cleaner spraying until the cleaner ran out clean. I still feel a very fine grit that I can't see when I touch the inside. How did you guys clean the inside of your housings? Do I need to keep cleaning until all interior surfaces feel smooth?  Should I try pressure washing the inside. A friend recommended steam cleaning but I don't have access to a steam cleaner, I could run hot water through my pressure washer. I definitely want all the grit out before I reassemble everything. I don't know if the grit I'm feeling is blast media or burnt grease residue.  Any suggestions?
Thanks

[XS29LA47V21]

Lots to worry about, the last two I did I moved past it with the thoughts that all "sediment" will fall and lay in the bottom ok that did not make you feel better, sorry.  I found several crevices the blaster missed with the grease caked with sand NG (no good), it remained after PC baking, I blew it out dry first, wiped the very best I could get to then used degreaser with hot water pres washer (a buddy's), blew it dry, then applied my first statement to the rest...