Many people, I think, have been asking for this.

Paint Bucket - White
Just a white paint bucket.

Wall Brush
Paintbrush that paints only the wallpaper. Recipe could include paintbrush.

It is either the Paintbrush is revamped to paint blocks only, or this:
Block Brush
Paintbrush that paints only the blocks. Recipe also could include paintbrush.

In this update, the paintbrush still functions the same, paints both wallpaper and block, there is just a way to upgrade them so it could paint a specific element.