Originally Posted by
manneca
Assuming you can get access to the sensor somehow, try holding the camera upside down and using a blower (NOT compressed air) and blowing dust off the sensor. I have tried eclipse and swabs on my MarkII 1Ds and actually blowing the dust off worked better. Using the swabs is dicey because you can cause permanent damage.
I'd agree except for the fact he has a streak. Unless there's a hair in there or something like that he's going to need chemical solvent. Plus I've seen dust that's stubborn enough not to leave with just air.
In any case, a cheap, easy way to blow air onto the sensor is to buy one of the earwax removal kits for a few dollars that include a blower bulb. Works great and is small enough to carry with you.