just been to see my grand parents and grandad gave me a block about the size of a large match box and said its for polishing stainless steel its like a hard sponge and im not sure what it is
if my camera works tomorrow ill pop up a pic

Hi

I have a block that is like a pencil rubber ( eraser ) impregnated with carborundum.

Does this sound like it?

It is used for removing weld discolouration from grained stainless sheet.
( Rub with the grain )

HTH

Paul G

I used these years ago - there were several grades which were suited to polishing alloy and other metals. I remember spending loads of time on my old BSA polishing up all the rocker covers which came up a treat

thats the thing just asked the chap who finished my exhaust today

They are called resilient abrasives blocks.

a bit sad but ive just written that down as several people have asked me