I was wondering if getting a new Book of Shadows is an option. I got one around 10 years ago and, while it is nice, I don't feel a real connection to it. I would like to find/make one that's more suited to who I am now.
That should be pretty easy... most people I know of like to hang on to their old, full, or decommissioned books though. Even after transcribing what you want to keep into your new volume. Think of it as a closed past chapter in your life, and save it to look back on. It is a neat snapshot to look at three or five or fifty years later so you can have a concrete then-and-now look at yourself.
Even if entries feel like rubbish now... or inspire actual cringe even. Seeing that, and reminding yourself how you have grown/moved forward can be a huge morale boost if you have been feeling like you've just been spinning your proverbial wheels since 'forever'. It can reveal inner motion and growth you didn't realize was taking place.
In the end, however, if you do decide to trash your old work it is as simple as making use of a paper shredder, a fire pit, or dropping it into a bin on garbage day. ...It is just a book, after all. A few pages with scribbles and notes and ideas. The power of them comes from the reader, not the ink.
Though, if you are looking for a more formal personal release, i suppose you could make a mini-funeral out of the process. Anoint the book, place a candle near it, call on the deities you worship/follow and dedicate the effort and learning within its pages towards their glory in thanks, then commend the book to the earth by burying, or burning and scattering. That way you are not throwing away your past or effort but instead naming it as effectively being a sacrifice and thanks to the honor of your guiding forces.
The idea behind it is that your guides gifted you with experiences and inspiration, their effort being reflected in the resulting pages of your gained knowledge. So you are presenting that knowledge back to them as a gift in return.
