Why not? and then soak it in mouthwash of different colours (blue, red, green..) for a couple of hours. Rubbing scrubbing soaking fun!
If you don’t brush your teeth all kinds of things gets stuck in between. With your negatives, its important that you keep the sprockets clean!
Following ingredients: Baking soda toothpaste (hard to find as the companies try to sell baking soda as “micro-crystals” or other creative paraphrases), I took 2 different brands/types to see if there is any difference. Extra baking soda, just in case. Mouthwash, green (extra mint, yum!).
First try: take a bit of toothpaste and scrub the negative. Not much to see except some pasty stuff, off to the mouthwash.
Second try: bit of toothpaste and some extra baking soda, longer rubbing. This time some thicker pasty stuff and obviously the negative loses some colour, off to the mouthwash.
Third try: the other toothpaste, impatient heavier rubbing. Obvious holes in the emulsion, off to the mouthwash. I let them soak in mouthwash for more than 18 hours before i took them out.
The rubbing creates tiny scratches in the negative, and if you go on and on you will finally scratch off the whole negative. The toothpaste doesn’t add much to the scratching (it’s supposed to softly polish your teeth, not to grind them down) but leaves some smudge behind. The extra baking soda isn’t noteworthy either.
And the mouthwash… as your teeth are not green after using it, I’d guess the colouring potential of it is pretty low. And after an 18 hour bath there is no trace of colour effect. At least the negative smells like “waking up in a wild mint field at sunrise”-image painted with neon ballpens.
These Lab Rat experiments might not have been the most spectacular ones result-wise. But they showed one important thing: You can really try hard to do cruel things to your negatives, they are still OK or at least not completely destroyed (unless you are really enthusiastic about the act of destruction).
Which means: Analogue rules! Long live the negatives!