If only paint or primer were used, the roller would require cleaning each time and the lid on the paint can sealed. It would work as well as cans of spray paint and be cheaper, but more work.

The oil-paint-grease mix never, ever dries or hardens. Rollers are replaced eventually, but never cleaned. The lid on the bucket is just placed over the mix, not sealed.

Thanks for idea of only cheap paint in a bucket

But we tried cans of spray paint, and never again.:)