Aroma-bead car freshie

Unscented aroma beads soaked in fragrance oil, baked in a mold until they fuse, and hung from a cord. A long-lasting car or closet freshener.

Use a baking sheet and molds you keep for crafts only. Don't use them for food afterward.
Ventilate while baking. Hot fragrance oil gives off strong fumes. Turn on the range hood or open a window.
Wear gloves when handling soaked beads. Fragrance oil irritates skin.
Never leave it on a car dash in direct sun or on hot plastic surfaces, because oils can mar the finish.
Hang it so it doesn't block your view or swing into the windshield.
Keep freshies away from children and pets. They look like candy and are harmful if chewed.

Steps

Weigh the beads into the glass jar and add fragrance oil at about 1 part oil to 3–4 parts beads by weight.
Close the jar and shake it well. Leave it for 1–3 days, shaking a few times a day, until the beads have absorbed all the oil and feel dry, not wet or slick. Add colorant near the end if using.
Heat the oven to about 300°F (150°C), and check it with an oven thermometer.
Line the baking sheet with parchment, set the molds on it, and fill each one evenly with beads, level with the top.
Bake 5–15 minutes, checking often, until the beads have melted together and look glossy but still hold their shape. Every oven differs, so watch the first batch closely.
Take it out and, while it's still soft, push a straw or skewer through for the cord hole.
Let it cool completely in the mold for about 1 hour, then press it out. Blot off any surface oil.
Thread the cord and add a label. Let it sit a day before hanging so any leftover oil soaks in.

Beads still round or crumbling after baking: Not baked long enough or too cool. Bake a few minutes more and check your oven's real temperature.
Oily, wet freshie: The beads were baked before absorbing all the oil. Soak until they feel dry, or use a little less oil next batch.
Bubbling, scorched or flattened freshie: The oven was too hot or it was baked too long. Lower the heat toward 275–300°F (135–150°C) and watch closely.
Scent fades quickly: Heat in a car burns off scent faster. Use stronger fragrance oils and keep it out of direct sun.