Toothpaste and canopies?

Yup, it's true. Get some toothpaste that contains baking soda and just use the paste as a rub, wash well afterwards, let dry then dip in Future.

will baking soda-less tpaste do the trick?

Yes and no:

You need a 'bad' brand of toothpaste. Good toothpaste will not sand that well. Good for your teeth, but it will take forever to polish your canopy. I use Tamiya polish paste, which works just as well (on the model; not for brushing teeth; although I never tried).

hehehe... i spose u could get a whole line up of different polishes outta different toothpastes .
ive heard that the stuff old ppl use to clean their dentures is particularly coarse...

For something faster than toothpaste, you can use nail polishing sticks. The one I have has three surfaces and it did a super job with some canopy modifcations. Basically I ground out the inside of a 1/72 Spitfire's canopy hood, so that it would be thin enough to look good posed open. After sanding with various grits of sand paper, I used the three surfaces of the polishing stick as well as little swatches from each surface wrapped around a toothpick to get into the corners. Once I was done with the polishing stick, I finished up with tootpaste, although I don't think the toothpaste really did anything. A dip in Future and the thing looks perfect.

That's kind of weird. Two toothpaste-canopy topics. Sorry about that