Nuke special characters in Sitecore RSS feeds

 If you have a problem with special characters displaying in Sitecore's built-in RSS feed, there are a few options to consider.

You can simply strip them out, but that could lead to some undesired display issues.  Decoding them before display can be time-consuming as this is out of the box Sitecore.

One quick way is to review and adjust the Rendering.HtmlEncodedFieldTypes setting in the web.config.

Changing <setting name="Rendering.HtmlEncodedFieldTypes" value="text|single-line text" />
to simply
<setting name="Rendering.HtmlEncodedFieldTypes" value="text " /> fixed the problem in at least one case.

As a caveat, you'll want to be careful when changing any setting related to HTML encoding, as that will impact more than just the RSS feed - but it's certainly worth a try if you experience this issue!