Cleaning SMC-A 50mm f/2.8 Macro?

Recently procured one of these for a decent price (were it clean), so notified the seller who issued a generous partial refund (so more decent given the condition), yet I want to clean it. The outer elements are both immaculate, no scratches etc. but the inner elements are harbouring a fair amount of dust.

Is there someone who I might be able to send this off to for a CLA, or anyone with suggestions on how best to clean it myself? I don't mind paying some £'s for this to be sorted as it's a lovely little beasty which I am already a fan of, despite the current foibles.

Much appreciated in advance!

P.s. I've already checked the 'lens cleaning/disassembly' page from Pentaxforums and there are no guides listed on there.

Brilliant! Thanks for the speedy, helpful reply Mike.