When the putty is completely dry, scrape it off with a coarse file. After that, polish with a fine file. The degree of sanding depends on your preference for the finish.

File rounded together and sharpened. It will be easier to control.

If you like the uneven look, just a coarse file will suffice. If you want a smooth and clean look, use a fine-grit file.

The filing process is most important in determining the finish of the kintsugi.