Related Clues:
- It will pay you to keep it running smoothly, perhaps, like this
- How boring to have to make it and keep it properly lubricated! (3, 4)
- Money comes gushing out of this, so keep it running smoothly
- Keep it properly lubricated - that's the drill
- Keep thoroughly lubricated - that's the drill
- Painting's deeply boring
- Instruction to mechanic might be a bore
- Eliminate all friction from fuel source
- Base of rig — lubricate generously
- Shaft to extract fuel
- Boring - source of petroleum
- Source of fuel
- Whence petroleum is extracted
- Source of 'black gold'
- Borehole for petroleum