how to dismantle a powermac g4 mdd?

Hi Leonard and Welcome to Apple Discussions,
I blow out computers using and improvised "leaf blower" that I made from an old vacuum cleaner converted to blow from suck. I also brush them off with a clean paint brush.
If it's really dirty and the dirt is really stuck on it it would require dismantling and cleaning with deionized water, blowing completely with compressed air and drying for days best in a drying oven.
If you want instructions email me.
Richard

Yeah, I'd be interested also.

Hi-

To remove the logic board:
-Disconnect all cables connected to the logic board.
-Remove any PCI cards, and RAM.
-Find and remove the five screws that hold the heatsink. Remove the heatsink.
-Remove the processor board by lifting the edges. Slide the processor board to the rear and lift out, being careful to clear the two mounting pegs.
-Find and remove the one screw that holds the logic board.
-Slide the logic board away from the back panel, lifting to avoid the chassis hooks.

To remove the side cover, after removing the four screws on the exterior, look to the center of the where the logic board was. You will see two plastic tabs (semi-circular) sticking through the case door. Carefully squeeze the tabs together, and push out, allowing removal of the side cover.

After the heatsink has been removed, the processor is removed by lifting the processor board up to remove it fron the logic board. There are no screws, but there is a large connector that the processor board is pressed in to.

Try Googling for 'Service Source' and the name of the mac.
Mactracker is an application that lists mac models, it helps to decipher which version you have, then Google for the Apple manuals. There are various pdf manuals that have full take apart instructions.

Totally unexactly , How can I safetly remove de CPU Board , i need help with this ,no seems to move to any direction , how exactly unplug it?