You only get one clean slate. That’s when you are a kid. After that, you can scrub at it, but it’ll always be a sort of palimpsest, with bits of the old layers faintly showing from below. So you can never totally scrub it completely clean. I don’t think this is a bad thing. It’s part of learning and incorporating the old with the new.
Being in a craft or art is the same way. First, you start fresh but soon find that answers often are found by working through mistakes. Some people take the process of working through failure as a sort of crusade. “Onward, despite the cost!” I’ve found it’s wiser to put a loss aside for a while and move to another project. Leave the puzzle where you can see it, and let your mind nibble about the edges of the problem. Eventually, you’ll solve it or leap ahead into finding a different way of doing things.
Thrusting blindly at a problem wastes energy and leads to frustration. As in war, so is it in a craft; the value of frontal assaults is greatly exaggerated.
The process of attaining mastery is one of learning, making errors, correcting errors, learning effective habits, and freeing your mind to be creative. A pivotal concept is that learning is not a one-way process. You backtrack, learn new things that overwrite old ways of doing things, make modifications, and synthesize the new out of old all the time. You have a palimpsest.
If the term master is disagreeable, try this one – Old Head. An Old Head is a person who has been around, learned the ins and outs, works efficiently and makes it all look easy. Warning: Old Heads are not necessarily good verbal teachers. I had a Judo Sensei who could not tell you how to do a particular throw, but he’d show you a thousand times or until you mastered it.
Old Heads are not always formally taught. Old Heads work on railroads, in boatyards, art studios, and factories. If you need to learn something, look for an Old Head. Their clean slate days are long past, the smudges and stains are there to be seen, but they are a wonder to watch at work.