Cleaning D30 sensor w/o AC adapter

I now have the 10D and I'm selling my D30. I have decided to

keep the double battery charger that came with the D30 because

I often simultaneously use my G2 (and later will use G5) with the

DSLR and it makes recharging more convenient. So I'm going to

substitute the single battery charger for the original one that

came with the D30 kit.

One buyer was concerned about how to clean the sensor without

the AC adapter. The double charger accomodates and comes

with an AC adapter while the single one does not.

The 10D will allow the user to enter the sensor clean mode with

a battery installed, but the D30 will not unless the AC adapter is

attached.

Fortunately, I have never had to clean the sensor on the D30, but

I've been told or read somewhere that an easy work-around is to

use a freshly charged battery and simply use "B" setting on

manual mode with a locking cable release to open the shutter,

thus gaining access to the sensor for cleaning.

I've done up to 4-minute timed exposures at night with my D30

and never had it try to close during exposure on "B" even with a

dozen or more of these long exposures, and this was on a

sub-freezing night in January photographing by moonlight.

I'm wondering if there is any down side to cleaning the sensor in

this way vs. the AC adapter and "sensor clean" mode found in

the camera menus.

The only thing I could imagine that could cause harm (other than

an unexpected closing of the shutter) would be some sort of

sensor overload from the abundant light without a lens attached.

But I wouldn't think that would harm the sensor, since there are

often blown out pixels from overexposure often as in light sky

areas, too strong flash settings, etc. with no apparent ill effects.

Has anyone tried this method to clean/access the sensor? And if

so, any advice, precautions?

Thanks