This comment is misinformed and should be deleted because it is so dangerous. HF will kill you for looking at it in the wrong way; please don't handle it unless you understand the danger it poses to you and the people around you.
Since this product is commonly available at hardware stores across the United States, why should comments related to it "be deleted because it is so dangerous"?
I agree that HF can be extremely dangerous, but in this case it's not clear that Sam is working with or advocating use of dangerous concentrations or chemcial forumulations of fluorine-based acids. Maybe I missed a post where he does discuss using more dangerous concentrations or compounds?