Just fill any bottle with water, jam the cork in and sprinkle away. What could be easier? (My answer: buying clothing that doesn't need to be ironed, but then that's just me).
Here's the whole vintage assembly available from an Etsy dealer:
Next, I'll find out that someone's still using these things! (The washer has a wringer to wring the clothes out, since there was nothing like a spin cycle. A stick was often used to feed the clothes in, so that fingers didn't get caught in the mechanism).
Have a wonderful day!