I'll go home and look for scotch brite. Wait until I go back to Ipoh first on friday. Thanks for the suggestion.Try Scotch Brite with some strong scrubbing paste, next is steel wool if scotch brite don't work. Of course final stuff to try is sand paper....
Scratching the surface only. Or maybe, I'll just colour them back with chrome silver marker pen. I have those.don scratch too deep using sharp object. steel wool is better.