OK, I'm not very good and creating How-To's but I'm gonna try anyway. I've already finished the job but I did the process over to show you how I started and how I taped over the screen and back to do this.
Supplies: Electric Tape, Scotch Brite Sponge & (of course) an iPhone
1st: you want to use the electric tape and cover the edge of the screen as close as possible the chrome trim. Repeat for the back also..
2nd: use the Scotch Brite sponge and lightly rub one way & reverse.. Ex. Whichever side you start on first (I did one side @ a time) you want the sponge to meet the two corners. Keep going back n' forth till you get the look you want..
3rd: Because of the tape the corners we're probly covered like mine and you still have a chrome finish on them. This is were you have to be very careful and take your time. Cause you will have to do this freehand unless you have a way to cover the edge of your screen to brush the rest of the chrome. Once you've accomplished that your done.
The pics attached I have tape on the longside of the phone. You would repeat that same tape scheme on the top and bottom of the phone.
This isn't the best of tutorials cause I suck @ these types of things. Feel free to ask me any questions that you may have if you want to try this. Goodluck!