Kanban stamps candle.  I at last found out how to do this... it sounds so easy.... and it was!  This was the first one I did and I'm going to give it away as a present.

You do need to find the right kind of candle though.  I did buy a pack with 5 candles for a pound - which sounds great but they were cream coloured.  That would still have been fine, but I found that the wax melted and left a slightly different colour underneath.... I won't be giving those away!