Free long lasting aluminium Bonsai labels

If a new Idea starts with a can of beer you already know that you are on to a winner. I am not good at keeping good records of the work that I have done on my trees. I have used plant labels but they fade, get lost and are easily misplaced.
I have priced commercial aluminium tags but they are expensive when you need hundreds. Soft aluminium words well because using a biro on a soft surface makes an impression that cannot fade, washed away or deteriorate.

I have looked at lots of options but have come up with a solution that is FREE, recycled and easy to make.

I use abbreviations on my labels: RP= Repotted C= Collected

1 Open an aluminium can of beer

2 cut open the can with strong scissors

3 cut the labels to the size you want

4 use a hole punch

5 write with a biro on a soft surface

6 attach to the tree with wire