Sclerotia are physarum' emergency store - a slime mould potato that can wait out harsh conditions.
They can be stored for years and are easy to wake up which makes them a really handy way to give out cultures of slime.
Put a filter paper in a petri dish and dampen in (kitchen towel, ice cream tubs etc will be fine)
Put your dried bit of paper orange side up in the middle of the petri dish and put a single oat flake next to it.
Leave it somewhere dark overnight.
The slime will wake up and will start to eat the oat, once it's fully covered it, add a couple more.
Keep it in the dark and gradually increase the amount of oats at each feed, once you have something the size of a 10p then you're ready to move on to the next stage.