Cleaning a mattress

[MrsCosmopilite]

I should point out that there is nothing horrible that has been spilled or smeared onto it.
However, it's a fairly new (and expensive) Kingsize mattress. It's usually covered by a fitted sheet with another sheet under that, but is showing a small patches that are discoloured (presumably perspiration leaching through).
The cover on the mattress is padded but non-removable, and the mattress is a fancy all-signing, all-dancing one with special temperature control beads so you can't flip it over, just rotate it, IYSWIM.

How can I clean it up before it gets scuzzy?

Oh, and I don't have a spare bed to sleep in.

I've used lemon juice and bicarb for sicky stains / smells in the past, and dried with hairdryer.
I'd have to google the quantities though, was a while ago.

I would get a mattress protector for the bed and that will stop stains reaching the mattress

Thanks ThreeQuarters I'll have a google at that.
demented - I did think about that, but the fancy schmanzy micro granule things that regulate the temperature won't be effective through a mattress protector. At least, as far as I know. Perhaps I should google that too!
:)