You could try hitting them with a dull coat while you're dulling up the rest of the tank. Then you would probably have to dry brush a bit of steel back over the hight points. But it might work. I hit mine with a bit of Floquil dust and mud. That REALLY toned them down (almost too much). I've got to go back over with steel myself.
As far as how I initially do them:
First I spray them with flat black, then dry brush them heavily with Model Master (enamel) Steel, then wash them with a thin mixture of Humbrol #62 (sand) and a bit of burnt umber oil paint. After that, its just a matter of picking out the high points with silver.
Good luck.
Bill
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DML M4A2 Red Army
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-- There is a fine line between "hobby" and "mental illness". (Author unknown)