I have never had cause to use the product but I do have one experience.
1981, High School and the teacher is handing back our hand-written essays after marking them. She berated many of the class, me included, for handing in such shoddy work because of the amount of errors. That might be fair enough but then she held up one piece of A4 paper and did so in a way that the sunlight from the window came through it. "This" she exclaimed "is perfect and you should sll do better".
The sunlight showed blocks of what in the UK was called Tippex.
Teacher was clueless, but the felllow student had done it very well.
1981, High School and the teacher is handing back our hand-written essays after marking them. She berated many of the class, me included, for handing in such shoddy work because of the amount of errors. That might be fair enough but then she held up one piece of A4 paper and did so in a way that the sunlight from the window came through it. "This" she exclaimed "is perfect and you should sll do better".
The sunlight showed blocks of what in the UK was called Tippex.
Teacher was clueless, but the felllow student had done it very well.