How to sharpen a metal tip on a wood burner?

Question

I believe the tip is made of brass.  It has a blunt tip but I need it sharper to make finer lines.  Any ideas on how to make is sharper?

Update:

I was dumb and got the kit that don't have replaceable tips

Answer 1

Favourite answer

Spend $50 on something you don't have to damage to do the job.

Answer 2

get a new one in the size you need

Answer 3

You buy a new kit.