Glad to help!
The first time I did it, was a hoodie that had been washed. I put a name and number on crooked. During the removal process I used less chemical and more scrubbing. The key was heat pressing it before I laid down the new vinyl. After it was done, you couldn't tell it had any issues. But I also put the replacement in the same location, which would actually cover any imperfections to a point.
This past weekend, we did gold vinyl on some American Apparel hoodies and Next Level t-shirts. These were brand new. One hoodie the art was placed too high, so we completely removed it and put it in the right spot. You couldn't tell there was ever any vinyl in the old spot.
What I started doing now is getting enough spot cleaner on it to loosen the vinyl, then peel it up. Then I'll wet it some more, take a clean rag and wipe it away, then press it, then apply vinyl. I didn't use as much of the scotchbrite as the first time, used more chemical.
One shirt we did, we had to change a number 7 to a 1. The rest of the print was ok. It was a challenge, but we used just enough to get the number off without disturbing the other numbers. And in that case, if we get the other numbers wet, I would immediately heat press to remove any of the chemical so it can't start lifting in spots we don't want it to.