And I agree with both Scott and leigh here.
Those brown bits are rust and mean the whole sifter should be tossed into the trash ASAP.
I wouldn't wash a sifter any more than I would wash a pasta roller. I would simply tap (in the case of the pasta machine, brush) away the majority of flour, then store in a ziploc or other bag and not worry. Flour doesn't attract any poisoning critters in its dry state, so there's nothing to worry about.
I don't use a sifer, though, and haven't in years. Like leigh, I opted for fine-mesh strainers since they are so much easier and faster to sift with. It also much easier to incorporate soda, baking powder and salt and the like. Definately don't shake, but tap if you want to limit the spread of the stuff.
If you wish to use a sifter, and many prefer them, either use a stainless steel model (definately worth the few dollars more) that can be washed, or never wash the thing. I'd personally still use a stainless model, regardless.
Pain is inevitable. Suffering is Optional.