Hi,
First, it's not special characters. It's HTML entities. Search engines, like browsers, know how to read them so I don't see why that would be a problem.
Second, these are dropdown values. Dropdowns are not taken into account for SEO. So displaying them without html entities shouldn't help you at all regarding SEO.
If you want to have them taken into account, you should write them in the description, or in the meta data fields of the product like the meta description, or the keywords.
Finally, the other thread you wrote was in the showcase section of the forum. These messages are rarely moderated so it's normal that you didn't get any answer. I've deleted it from there.