[noshed]

I used the one that came with my B&Q labels. And it faded completely.

[ziggywigs]

Try the permanent sometimes known as 'indelible' marker pen.

[ytyynycefn]

I bought a twin pack of "garden marker" pens for a couple of quid from the garden centre - look just like those Berol felt tips I had at school!  They work really well - one lives in the shed for allotment purposes, the other in the kitchen for lunch box and freezer purposes.  They haven't faded yet in the sun, yet wash off in hot soapy water indoors.

[freyaluck]

I use the cd pens you can get, never had them fade yet.

[Zak the Rabbit]

Ordinary pencils are completely waterproof, but might not write on smooth sirfaces like plastic tags,

I use a indelible black pen (permament OHP pen) and write on leftover wooden blocks!  (see me blog for a piccy)

I also use chinagraphs that i have left over from marking navigation charts and maps, and that i used to use to mark on photographic film