Thanks BR, will look into that.
There is one other "insert obnoxious ad" outfit that does not seem to have a solution, however. it is ABB YYY or something like that; has big yellow images in every corner of a page with a clickable "Buy Now" link.
While most of the image can be automatically removed with regex code like the above, they somehow embed the closing TAGS in the last section of the image within normal text, and it is random, not predictable. So if you look for a simple string with opening and closing tags and remove them, you remove some amount of normal text as well. Since it is a random process, the only way to get it out is a manual edit of every page.