Little white dots in tv modle# wdt657 what are they how can i get them off

Your TV is DLP projection TV. DLP is Digital Light Processing. Digitally processed light coming out of DMD (Digital Micro mirror Device) is projected on the TV screen. This DMD is made of thousands of tiny mirrors & the size is about 0.7 inch. These mirrors are fixed with tiny hinges for its movement. They reflect light as per processed signal. DLP is invented by Texas Instruments. When there are dots on the screen, that means the tiny mirrors representing the dots are stuck in its position. If the dots are few & the viewing is bearable, just leave as it is. If the dots are more than bearable then you will have replace the DMD chip which is quite costly.