Since originally noticing some dust a couple of days ago and giving it a blow with the bulb, I noticed that there is still a "bit" of crud - I'm not sure just what it is - in some of my pics when viewed under auto contrast or auto something in photoshop and set at F22 or above. I know it can't really be oil because I gave it a blow and that got rid of some but it also moved other stuff around. Blowing the sensor, or filter above it, wont really do much anyway. Today I used the Arctic Butterfly on the surface and that "moved" a lot of it around and also got rid of lots of other stuff. I wouldn't have even worried about it,, only there was this one big mark that was almost appearing on any normal blue sky shot, even at F7 - 8. It didn't look like a dust spot but had shape and length and for a second I thought it was an oil smudge. The Arctic Butterfly got rid of that but there is still lots of tiny stuff on those auto contrat pics, that doesn't show up normally. I am going to head into town during the next week or so and get some of those "Visible Dust" sensor swabs or paddles or whatever they are. I already have some but they are for smaller sensor sizes like the D300 and the fluid has probably gone off by now, so a new bottle of that too. Actually I have a container of lab grade Methanol (or os that ethanol) but I am a bit scared of that stuff as it is very potent stuff and really, that I know of, shouldn't be splashed onto your skin or breathed in, as many believe it to be super bad for your internals - may cause cancer and so on...
Personally I am not scared to swab the sensor/filter as I have done it before. It's really quite easy...!!!