Hi Sircharles,

Here's a rough bump map example I did quickly for some of my students a couple of years back, for the top of an aluminium can.

Feel free to use this, or refer to it when making your own. You will need to load this file into the Bump attribute of your Material that is applied to the top of your can.

Hope this helps!

Simon

PS Not sure what your level of proficiency is, but I had my students apply this texture using UV co-ordinates, although you could also use projection mapping if you are more comfortable with that!