Painting battery compartment

[sailcapt340]

On my 2000 340, my 4AGM Group 31 batteries are now out. They died!
But now I have a very dark and dingy battery compartment. I have tried all kinds of cleaners but the area has rough textured walls and a composite flooring (hatch access to the Waste Holding and Fuel Tanks (on the other side but I might as well do both) that make it impossible to clean.
Has anyone cleaned and repainted their battery compartment? If so what did you use. Thank you for any input.

 

[SG]

What is the "dark and dingy" from? What's coating the surround? Was that from days when there were some lead-acid batteries that "died-in-place"? What's making it dirty, other than just "faded"?

Can you take pictures of the conditions?
I suppose you could epoxy coat it with a trowel-on coat if it's really "porous", then sand it lightly and paint over it with a compatible enamel paint.
You really shouldn't need to wipe it down.

 

[sailcapt340]

Originally I had 3 Lead Acid Batteries as you said. Faded, yellowing is more accurate. I'll be on the boat tomorrow and post a few pictures.