Glittering Spores can be found from Glittering Mushrooms in Faron Woods in Skyward Sword. Link can slash at any Mushroom in the woods to collect Mushroom Spores, but Glitter Spores can only come from certain mushrooms that are glittering. After slicing at the mushrooms with his sword, Link can swipe an Empty Bottle to capture these Spores in said bottle.
Each time Link collects Glittering Spores, he will have 5 uses of them. Link can use Glittering Spores on Rupees and it will have a random effect. If used on a Green Rupee, it can change to a Blue Rupee, a Red Rupee, or even a Rupoor. Link can also sprinkle Glittering Spores on a Recovery Heart, causing it to change into a Fairy. It can also be used to stun enemies, pour the spores on the enemy and it will be stunned for an amount of time. Link can dump the spores on hard to catch insects to slow them down. If he pours the spores on Gossip Stones, then they will shrink until they disappear, causing a new one to appear.