hi
my x-5 has the bead blast finish low luster mag bases and jet funnel, but they are discoloring, perhaps oxidising? i am not sure if i have put oil on them and they shouldnt be oiled or why...any ideas on how to remove it other than polishing which will give me a shiny non original look? thanks in advance

I believe they are aluminum alloy. An abrasive like Scotch Brite would satin finish them. Only way to keep them original is fine bead or sand blast. You can halt oxidation with a fine spray lube like WD40, BreakFree or something of the like. Keep in mind, being a sand blasted finish will also pick up particulates from handling when shooting and loading. Some of this may well come off with a nice clean, fine lube like Break Free.

thanks mate i was thinking that, i might just polish them

Mine are all in the exact condition you describe.