I'd do the washing - there's a lot more risk / complications possible with unwashed sperm being used in w/ IUI

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Mar. '08 - 1st IUI ,
Apr. '08 - clomid, IUI
May '08 last clomid run, IUI (clear HSG)
Jun. '08 - 1st IUI w/ follitism
July '08 - 2nd IUI w/ follitism