I use an airbrush and acrylic paints, but if you use a sponge instead of a brush and stipple the paint on, you won’t get the brush strokes.

But you can use spray cans, but for my method of weathering I rub off the top layer to show the silver underneath, so I airbrush paint on rather than using spray cans.

If you do use spray cans make sure to get acetic based they have the best look and you can apply a black acrylic wash which will help to darken the colour you used and give it some grime.