I found some lovely, soft, low-loft cotton batting in my stash - and of course wondered how it would dye.
The rust is from a hanging basket that's been happily rusting outside for the last couple of years - I peeled the last of the plastic coating off earlier this week.
After soaking the fabric in water and white vinegar, I pegged it around the basket, wrapped it in black plastic, and then literally forgot it for a few days. When I unwrapped it, I found the base was sitting in a puddle of rusty water, which explains the circle.
Once it was washed, I used a teabag of Bell tea - which turned out to be a horrid powder, rather than leaves, to make the blue-grey semi-circles on the second image, and some decaf Moccona to make lighter blue spots on the first image, which is the other end of the fabric.
I like the bluey-grey colour that resulted.