You normally remove the whole blade. It should move back away from the U of the arm once you have pushed a retaining clip or nib. Some retailers will fit new blades for free or a nominal charge.
Thank you all for your response...my mistake...let me qualify my question----my wiper is more than 2 years now but still wiping good, but there are some rubber residue/marks left in the glass which causes glares from oncoming cars at night, so how can I remove those residues/marks? Thanks in advance.
No substitute for an experienced friend/brother/dad/uncle showing you. There are a handful of different methods, and some often involve cussing and minor blood loss/ fingernail damage! Check YouTube for a vid for your car, if ya lucky.
which, the seal around it to the cab or the rubber on the wipers?
Just go to Advance Auto. They install wiper blades for free. You can watch them do it so you can do it yourself next time.
Razor blade
Depends on the car as it may surprise you to know every maker has a different system.
windex
