Trouble removing freshly cured silicone


Reefing newb
Just stripped and resiliconed an older 125 gal tank, and because of a small mistake I didn't notice now I'm having to re-resilicone the whole thing again. After spending hours just rigorously razoring all the freshly cured silicone off I go to clean and retape for the new silicone application and what do I find but my good masking tape is not sticking in certain locations, even after cleaning all the seams with denatured alcohol and then acetone. Although visually the glass appears clear in these places the only thing I can imagine is that there still remains a very thin layer of that freshly cured silicone that I'm not able to remove. In those spots I've put so much pressure on the razor I was afraid the blade itself was going to break in my hand. Been using the regular rectangular shaped razors with small removable handle for support.

So now I'm just about clueless as to what to do next. My only idea as to how to remove the silicone mechanically would involve some kind of spinning flap pad like you would clean metal with. It would be 'ok' to get into the glass a little as the upper and lower brace frames would cover the damage. As for a chemical means to remove the silicone I'm not aware of any due to silicone's nonreactive nature.

Any advice at all?
DAP makes a product to remove silicone. I have used it but not in a tank so I couldn't vouch for it being reef safe.