<p>Well,as we say, better late then never :-)<br>
Do not soak or flush the shutter completely. That will result in old lubricants being partly dissolved, transported by the fluid (naphtha) and deposited somewhere else.<br>
You could try a partial flush however, just the escapement, and let the flushing fluid run directly out of the shutter. If you are not familiar will these things (opening shutter etc.) then practice first on a similar shutter from a thrashed camera.</p>