Hi @Slim, certainly embossing, reed tuning etc. but to start I strip each instrument totally and start with the comb using a glass base and gradually working from 400 to 2000 wet and dry to get it smooth, not just under the reed plates and the plates themselves but where the slide goes, then the slide gets a going over, removing any burrs, cleaning each hole and ensuring it fits exactly to the mouthpiece. Next the mouthpiece using fine grinding paste is made to fit against the comb so as to minimize air loss around the two part slide. need to be very careful doing this, it’s easy to take too much off. It can take me 2 - 3 days to get an out-of-the-box chromatic how I want it and for final finishing I use toothpaste, apart from anything else it tastes better than grinding paste! It’s all part of the 20/80 rule, only 20% is really effective but it’s not knowing which 20% so the other 80% has to be done as well. Jay1