I do the same thing on the back porch (cement) with tweezers/forceps, candle, and small pan of water. I set the candle on a piece of foil in case I drop anything. I never do this on a windy day.
I also keep a log book with a swatch of the tested fabric, color of the flame, what the smell was as it burned, observations of how it burned (did it melt, burn cleanly, make little bead, etc.), texture of the residue/ash, and I use a wide piece of tape to collect a sample of the ash/residue to add to the chart.
This way if I ever forget that particular fabric and have more, I can go back to my log book. You can take the "fairy" out of the lab, but you can't remove the nerd from the fairy.