Prior to 2004 there was no license to produce the official Juventus printing. Thus pretty much anyone could find the correct font and proportions and next produce “the official” Juve name and number kit. Among those who did so was the English company Metro Sports. Now 20 years later that same printing can still be applied but it comes with certain challanges.
What can be seen from the photo is that paper backing is hard to remove, and that once removed it leaves marks with a mixture of glue and paper that goes nowhere.
However, with dilligent peeling and scrubbing the residues can be removed. Eventually.
The recommended application instructions say the following:
140 degrees, 10 seconds, medium pressure, cool peel.
However, since the printing is so old the recommeded instructions are slightly different: 150 degrees, 20 seconds, medium pressure, cold peel.
The numbers are even more complicated than the letters to clear but it can be done. Chemicals are not really the way to go. The best way to remove the unwanted leftovers is by simple water and a good scrubbing or scratching. Either by hand or by nail.
If washed in machine or by hand the leftovers will probably wear off. If not immediately then at least gradually.
The small ruptures are due to an extension of the experiment trying to remove the backing while still hot out of the press. That experiment obviously failed though. (also) one might add.