Smooth surface is all...
Rotary tool with a sanding drum here.
I am going to try to be more careful removing the tabs on the negative end in the future.
I use a ‘junk’ knife that is sharp and carefully scrape away the burs that are left.
I have trimmed the positive end tabs and folded them down to create a small ‘button’.
As long as you’re careful to only use those on a light with a spring on the positive end. The sharp edges will tear up a solid positive contact board….smooth is better all around.
I try to lift pointy bits with an old sharp knife then grab them with a cheap pair of small side cutters to see if they’ll pull off. Then I use a fine file until the surface feels smooth. I’ve never tried a Dremel.
All my torches so far have springs on each end so I’m more likely to damage ME than the torch internals if I don’t smooth the ends.