Have 2005 WD-62528, clean filter,good lamp, but have small randomized red, blue purple blotches apparently being projected on the rear of the screen. They don't move with the images so I suspect possible foreign deposits on one or more of the lens elements... how do I get to them and to clean them?

I strongly advise against opening a lens for any reason. You may not be able to put it back together!
In most cases issue is with some dust on the external lenses.
For cleaning the outside surfaces of lenses, lens tissue and lens cleaning fluid is fine. Both are available at camera shops. The fine camel-hair brush and air-blower-squezzer combo also works great.
If you suspect that issue is with internal components use compressed air to clean that.
Let me know is this will not resolve the issue

Clean lens element with soft hand karchief with very softjhand withg iso propile chemical then it clean

Hi, this may be as a result of missing pixels which are common problems when dealing with televisions

as an example here is a link showing how to deal with missing pixels on a lcd monitor:
>http://www.wikihow.com/Fix-a-Stuck-Pixel-on-an-LCD-Monitor

this is an article on missing pixels
>http://news.cnet.com/Consumers-see-red-over-dead-pixels/2100-1041_3-5579493.html

I would say that if this is the problem then you have the option of trying to get it fixed, replaced or return the item.

I hope i have helped you, sorry if i didnt

Good luck!