I'm documenting a project for delivery at Coronation. In the process, I took pics of scraped fixes of my mistakes.
Each piece of parchment is different - I had brilliant results with a previous piece, while this one is slightly fuzzier, and it is proving a bit resistant to a perfect cleanup.
What I know of scraping and fixing I learned from Lady Trinite (who gave me a brilliant sharp sculpting tool) and Mistress Bridget.
merlyn_gabriel's advice is very cunning: when you've made a mistake, write in the correct letters on top, and then scrape only the bits you need to - rather than scraping the whole word bare, and then writing in the correct word. You'll find you 'reuse' a lot of strokes, that don't need to be scraped, and can fudge more fix with less scrape than you think.
Mixed-up phrase (should be 'is bestowed' with a weird W) but started as 'the [something or other]'
The final result was a bit tidier particularly the second long S, but the pic didn't work.
I have burnished the parchment further, to try to soothe and smooth the fibres that are still fuzzed from scraping, but could not get the flawless you'd-never-know-there-was-a-mistake outcome this time.