They are just another form of compressed files, as zip files are. From some conversations here, I found 7zip. There are also others, just google or put rar files in the search box here to bring up some of those postings.
7zip is easy to use. I right click on the rar file, and on the menu that opens, I choose extract here. All files appear, and I delete what I don't want.
Jo

Here is a link for a free prgram that unzippes rar files. Hope it works for you