I wanted advice on how I can "clean" and remove products from feeds that I don't like or have nothing to do with the theme of the site. Example comparator shoes and there are also clothes in the feed.
Where do you find this option?
On the admin home page, click Filters in the row of button next to each feed to add filters for a specific feed. You can also add Global Filters - button is at the bottom of the admin home page...
The Drop Record, Drop Record If Not filters and their RegExp versions can be used to drop products or entire categories etc. from feeds;
For example, to drop the category "Dresses", just add a Drop Record filter to the Category field with "Dresses" in the text box on the configuration page.
If you only wanted to import the categories "Boots" and "Shoes" you can use Drop Record If Not RegExp, using:
...that's the RegExp (Regular Expression), in this case, a pipe separated list of items to match, all enclosed in brackets (the "/" characters are the expression delimiters that allow modifiers to be places after the expression e.g. "i" to make it case insensitive.