Stainless steel fuel tank cleaning?

[PeterR]

I have a great matching pair ofStainless Steel 25litre portable fuel cans.Came with the searider,the trouble is one of them has had water in and posibly steel bolt and there is rust in it .I have scrubbed where i can reach with a scrourer on a stick and wire but it still needs the areas i cant reach.Its just fine dust like and not the can rusting.I have thought of perhaps rapping a stone in scourers and adding saop and water,then giving it a good shake.Anyone got a better idea

[codprawn]

aquarium gravel or coarse sand and water

[PeterR]

Thanks I have just finished it ,Remembered i had some lead shot in the garrage and took the filling out of the metal/plastic brillo pad then stitched it up.Gravel would have been as good.