Will a mechanical gauge work with the engine off...or when the key is in the ON position?
I also have my MAP sensor pulled and cleaned it with MAF cleaner. I feel this part is meant to be replaced rather than cleaned since you can't really take it apart like a MAF.
Can you do what ZeeJay1997 mentioned and test the CCV without having the engine running? I feel like there would be pressure if it's cranking but I'm not sure.
Since the engine has to be turning to generate oil pressure no gauge will work with the engine off. Cranking should be enough to build pressure on a mechanical gauge though. You can buy a cheap one at a parts store for around $15 and temporarily plumb it in instead of your factory sensor.
MAP sensors respond to air pressure not air flow so the don't really get dirty. Spraying a bunch of solvent into the sensor chamber is probably not a good idea.
The engine doesn't make enough vacuum or blow by while cranking to make messing with the CCV hose worth anything. You need to get it running first.