roggie

WordPress posts and pages can contain Smart quotes and other fancy characters. But Smartquotes and other special characters don’t work properly if you send the contents of a post by email. This plugin cleans up text so it can be emailed properly.
Instead of using this plugin you could use WordPress filters to reformat text, but WordPress filters cannot be used with PHP functions like strip_tags. If you use a filter to remove Smart quotes you can’t also use strip_tags to remove HTML.
Also, WordPress filters don’t remove all the characters that could cause problems. For example, double spaces are not removed properly by WordPress, and Europeans will have problems with the UK pound currency symbol.
This very simple plugin removes all sorts of special characters, including double spaces and currency symbols that WordPress filters don’t manage.
It also has an option to remove HTML.

Cleanup Text

Function to remove smart quotes, HTML and other special characters from text. Call the function with text as argument, function returns clean text.

Martin Lormes

Change the quotation marks, that are automatically rendered as smart or curly quotes inside your content, from the default English style (“…”) to anything you like, e.g. to Croatian/Hungarian/Polish/Romanian style quotation marks („…”), Czech or German style („…“), Danish style (»…«), Finnish or Swedish style (”…”), French style (« … » – with spaces), Greek/Italian/Norwegian/Portuguese/Russian/Spanish/Swiss style («…» – without spaces), Japanese or Traditional Chinese style (「⋯」), or actually to any arbitrary character combination of your choice. Of course you can turn off curly quotes entirely by picking the so-called "dumb" quotes ("…").

Smart Quotes

Change the quotation marks that are automatically rendered as smart or curly quotes inside your content.

Cleanup Text vs Smart Quotes