Why is it that under the kitchen sink is always disgusting? You find me a house with a tidy under-the-sink area, and I’ll show you somebody with too much time on their hands. Anyway, my under-the-sink was in dire need of a refresh after a pipe burst, so I emptied everything out, and got to work.
First, I’d suggest going ahead and cleaning out your trap while things are gross under there so that you don’t have to deal with it later. If the space is wet/damp then you need to repair any leaks and thoroughly dry it with fans.
Once totally try, sweep out off loose debris and wash up any food or other spills. Again, let dry completely. If there are other repairs or replacements that need to be made, do that now. Then, it’s off to the Kilz Premium Primer. This stuff is amazing. It will stick to most anything, cover stains, prevents mildew/mold, and fills in porous surfaces.
Get a good coat or two, as needed, of primer and then move on to the top coat. I like to use a high-gloss latex enamel in white like you would for trim work. It dries to a hard finish and is easy to wipe up. Usually one coat is all you need if you are using a high quality paint.
Now I have an under-the-sink to make you jealous! I wonder how long it will take for it to get filthy again?