Covering Altoid tin with polymer clay sheet

I made a tartan cane following Dora's tutorial (Thank you, Dora!). I didn't reduce it too well, the pattern have got deformed. But the colours are still nice :)))
Roll a sheet out of scrap clay. Place cane slices in a row, trying to match lines and colours. When all slices are in place, roll them until smooth surface.

It is important to clean the box just before covering it with clay. Wash it with a soap, or wipe it with alcohol and let dry.
Place a sheet of clay on to the bottom half of the box. Make sure there are no air bubbles are trapped between clay and metal.
At the corners of the box press the clay gently toward the box. While soft clay takes a shape of the box corners.
Very carefully cut off the excess of clay. The best way will be cutting it off bit by bit, say, first cut away 5 millimeters all around the box. then another 5 millimeters all around the box again. Then 2 millimeters and so on. This way you are not going to cut off too much clay. Smooth the edge of the clay sheet with your fingers, hiding scrap clay.
Bake the resulting half-covered box.

Cool down the box and cover the other half of it with the second sheet.

Decorate the box as you wish. Bake the box.