Here's a picture to what the jacket looks like:
Lol, not a real jacket for you; it's for your Wii remote! lol
I have a couple Wii jackets, so I'll happily answer your questions for you:
1. does the wii jacket affect the sensor? -
No, not at all! The jacket doesn't block the sensor whatsoever; it does the opposite matter of factly. With the jacket your hand won't get as sweaty.
2. if not how do i make the wii remote point directly to the point i want it to? -
Just simply point on the screen where you want the action to happen. For example, if you're aiming darts at a dartboard, then you can aim your Wii remote at the bulls-eye, and with the right skill and control; you could hit the bulls-eye!
3. can i clean the jackets? -
to this I'm not sure, but ou probably could. I'd just suggest cleaning it with water though; not soap. Also, I wouldn't clean it much, because it may cause the jacket to shrink or stretch out.
4. if so how? -
mainly with water. Maybe a tiny bit of soap, not much though.
If you have any questions, please don't hesitate to ask. =]