Manually remove temporal files windows 10

So currently I have 11,7GB of temporal files on the disc where windows is and I already tried to remove them using the graphic interface(Control panel-> System -> Storage -> Disc -> Remove temporal files -> accept ) but its not working.Stays at 11,7 GB. The question is how to remove the files manually and not cause a serious system damage and can I remove the entire %Temp% folder content and not break the windows its clear that i am going to loos data.