It's easy to make a mop. Make about 20 loops. Finally, cut through the bundle at the the opposite edge. You can tie the ends of the knotted yarn around a cork if you wish the mop to float, or leave it as it is and let it sink. When your killies have spawned, pull the mop out of the tank and squeeze it gently to wring out the excess water.
Fertile eggs look like tiny crystal balls, transparent and shiny.
You can remove them from the mop with your fingers, a toothpick, or tweezers. Within a short time of being laid, fertile eggs become quite hard, so you don't need to worry much about crushing them. Killie keepers incubate the plant spawner eggs in several different ways. Some store them in a container of water with acriflavine added to inhibit fungus growth. As the eggs develop, some inavariably die or are infertile.