How 'bout a craft supply called Squeeze Paints...little bottles of a
rubbery goo you can write on the bag with. They come in a full range of
opaque colors, stick on there good once they dry, and the lines of
squeeze paint have texture... you can feel the design, so if you need to
grab one in the dark or while flying, you can mark it with lines, dots
or other pattern.

Of course I get acrylic craft paints and just paint designs on my
luggage so I can spot it from a mile away. It doesn't have to be good
art, but sometimes I make 'em sort of flowery and airport personnel
(when I fly commercial) find them highly entertaining. My bags don't
look like anybody else's.

f
Ben Jackson wrote:
On 2007-04-07, RST Engineering wrote:
(Please don't tell me to buy color coded bags. It is hard enough to find
exactly the right size for a job without specifying color too.)

You could sew colored flags on...

Anyway, I just want to stencil a contents label on the outside of the bag
with plain old white paint

There's an instructable on screen printing:

http://www.instructables.com/id/EFAN6S16FTEQ2W3MOV/

the process is a lot like making a photo etch pcb. You use some goo on
some gauzy fabric which you expose with a transparency to harden the
areas where the ink won't go. Then rinse out the unexposed goo and you
have a screen.