Here is how I painted my metallic floored bases. The Imperial Navy Breachers would always be in some kind of ship (in my mind) so it seemed natural to do something like this for them.

Metal Flooring

1. Basecoat with a black spray. I used Chaos Black .
2. Ensure good, solid coverage with a thin coat of Abaddon Black .
3. Heavily drybrush with Gunmetal Grey .
4. Give the bases a lighter drybrush of Duraluminum , trying to hit edges pretty hard to give the impression of scuffs. You could even go back in with a brush and quickly pick out details that could have been missed.
5. Now, with Chrome , or any other very bright silver, pick out corners and areas you want to accentuate. I did most of these as edge highlights, but popped a few rough scratches and highlights within marks from the last stage too.
6. I then went in and reshaded recesses where the drybrushing had hit undesirable areas. I used Ratling Grime in some places and thinned Abaddon Black where I wanted it to be lots darker.

These bases should look OK-ish now. Before I attach miniatures I'd like to weather them and introduce a bit of colour. To make the environment look liked in and add some visual interest.

Weathering

1. Sponge or stipple small patches of Rhinox Hide onto areas that could be chipped and scratched.
2. I then glazed Seraphim Sepia , Agrax Earthshade and Nuln Oil individually and glazed over the bases in patches. These shades were all thinned with Contrast Medium and I did a couple of passes. I covered everything with these glazes and tried to keep the browns in areas where dirt/grime/rust would gather and the Nuln Oil over everything else.
3. Run some thinned Skrag Brown into recesses and stipple within larger patches of Rhinox Hide to create the impression of rust.
4. Within the last stages "rust", do the same again using Troll Slayer Orange . Make these patches even smaller so they are just a little pop of colour.
5. With Duraluminum I reestablsih any edge highlights that were coverred in the last few steps and add a few extra scratches and dings.
6. Finally, I paint a nice crisp rim with Abaddon Black .

I am very happy with how the bases look at this point, but wanted to add a few little features to the plainer looking bases. Here are a few ideas...

Blood Splats

Take a little Blood For The Blood God on an old brush, and blow droplets onto the base with your airbrush or an air duster. Be gentle, less is more. If you wanted to add a little variety, jabbing a little Berserker Bloodshade on roughly with an old brush works well too.

Blood Smears

I looked up bloody hand prints and smears on Google image search and tried to replicate them. I stippled Blood For The Blood God carefully and did smears with normal brush strokes. If you want to vary the shade, mix in a little black ink or paint. Again, a few light jabs with Berserker Bloodshade is a good way to add more droplets.

Sticky Ooze

Stipple on some Nurgles Rot in a small patch. You can vary the tone with some brown mixed into it, if you liked. You could even do it over some Typhus Corrosion if you wanted some chunks. Eww... For the stringy stuck to my opperatives foot, I mixed some green and yellow ink until the colour roughly matched Nurgles Rot , before mixing it with some Uhu glue. I then took a toothpick and dragged stringsbetwwen his foot and the dried patch.