Can I delete some folders of nokogiri and capybara-webkit inside of my rvm gemset?

Can I delete some folders of nokogiri and capybara-webkit inside of my rvm
gemset?

I was using a disk analyzer and I noticed in my .rvm folder two gems,
nokogiri and capybara-webkit, bigger than the usual:

Checking inside of them I found that for nokogiri there is a temp folder
and for capybara-webkit a source folder.

My question is: Is it safe to delete these folders?(Yeah, I'm a greedy
disk space saver) and why nokogiri is creating that temporary folder?
Because I have another gemset (with a lower version of ruby and nokogiri)
and there isn't creating that folder.