One of those household staples that can be used to good effect in your mixed media work is the lowly ball of string.
Here I've assembled some string, a soft foam paint roller and a support that's already well layered with various techniques ( palette paper transfer, alcohol inks, script transfer, etc.).
I run the string-encircled roller (ends tucked neatly under the layers of string) in some antique copper metallic paint,
There's more than one way to skin a string, though! Here I've randomly placed some string on a support, and then over-painted it all with a soft brayer rolled in paint.
On this support, I taped the string outside the edges of the mat board. I rolled a soft foam roller in paint and then over the matboard. Once dried, and string removed, it makes a lively background.