[nmsmith]

Good ideas all thanks. Asmenoth your oil stain sounds a lot like the petrol stain below.

As it happens I found the mixes I had remembered in an Excel file, although I can't remember where I got them from initially.

For the record, and if anyone else feels like using them: (all using Tamiya paint codes)

"Burnt Steel" -
4: x-11 chrome silver
4: x-12 gold leaf
2: xf-64 red brown

"Brake Dust" -
1: x-21 flat base
4: xf-01 flat black
5: xf-07 flat red

"Cordite Stain" -
1: x-21 flat base
6: xf-02 flat white
2: xf-63 german grey

"Fresh Blood" -
1: x-07 red
8: x-27 clear red
1: x-28 park green

"Normandy Dust" -
3: xf-02 flat white
5: xf-52 flat earth
2: xf-64 red brown

"Petrol Stain" -
2: x-19 smoke
6: x-22 clear
2: x-24 clear yellow

"Road Dirt" -
1: x-21 flat base
3: xf-01 flat black
6: xf-52 flat earth

"Tire black"
1: x-21 flat base
1: xf-01 flat black
1: xf-63 german grey
1: xf-64 red brown

I will have some fun trying these out at some stage. If anyone has any other top tips for other substances please carry on suggesting them!