Harry from Canada asks: Do you know know a good way to get letters off rolling stock ?
Excellent timing Harry. The very same question has been exercising the minds to be found on the Double O Gauge Association mailing list (you have to be a member to join but it is worth it).
The answer is, there is no "one size fits all" answer. It all depends how the manufacturer printed the lettering.
On Bachmann stock, for example, a cotton bud (Q-Tip for US readers) soaked in turps or white spirit will probably work. I know I've weathered locos with a wash of thinned paint and looked on in horror as the stupid numbers vanish.
Acetone (nail varnish remover) will also do the job. Again, apply sparingly and test on an inconspicuous part of the model first.
For more stubborn print, T-cut (a mild abrasive car polish) or Brasso allow you to polish the stuff away. The resulting bodyside will be shiny though so you'll need to varnish the model after re-numbering.
Finally, I favour the fibreglass pencil. This tool allows burnishing the numbers or letters. The photo shows a PO wagon I attacked with one to remove most of the letters, just leaving traces as though they had weathered off. It takes a little while and can leave a shiny surface but is very controllable and at least is dry so you can't drip anywhere.