It sounds like it comes from one of their Weathering sets - aka "makeup boxes". They are something in-between drybrushing and crayon pastels.
There is a set with burnt metal, and oil stain colors.
Weathering Master D Set
Item No:87088
Burnt Blue (for scorched metal look)
Burnt Red (for scorched metal look)
Oil Stain (for realistic brownish-gray oil stain color)
These finishes are really easy to apply, even with the attached applicator which looks very simplistic but actually does the job.
Hope this helps /m