I always remove my fork legs to flush out the tubes (with a bit of diesel) and then leave them inverted overnight to completely drain/dry out. Then refill and refit. I'm always surprised at how much dirt comes out of a sealed fork leg, but it does come out and if it's left in there, it's going to cause premature wear somewhere.
If you can't remove the fork legs, then I'd use the vacuum method, but refill, work the forks up & down and then quickly vacuum out again, before finally refilling one last time. That way you'll at least get rid of some of the residue of dirt that will be sat at the bottom of the fork legs as it will be suspended in the fresh oil you just poured in.
I hope that makes sense.