How Do You Disconnect the Electrical Connectors in the ECU Box

[steamship]

I've been trying to resolve an issue on the car, and was wondering if the source was coming from the ECU box i.e. water ingress.

Lo and behold, the inside of the lid was wet and there was about 1-2mm of water in the bottom. Of the nine block connectors, two were lying at the bottom, in the water. It didn't help that one had foam wrapped around it, keeping the water around the connector.

I removed all three ECUs, and they were bone dry, but I still cleaned them with contact cleaner. The big issue is I can't figure out how to pull apart the block connectors. Of the one I did do, the loose lying one, it was a case of using jewellers screwdrivers under each clip, and then a lot of wiggling to get the two halves apart. I want to do all the others as well, just to be sure they're all clean, but even with the others unclipped from the box, it's a tight space to work in, and some of them have very fine wires.

The second one that was lying in the water only has a single wire in it, which is a power wire, going by its size, and that has quite a bit of corrosion.

The other question is how to clean the connectors once I get them apart, as contact cleaner won't remove the corrosion.