Which buildings produce Slag?
The publisher-hosted wiki lists the Toolsmith as producing Tools and Slag. Community resource tables add the Metal Smelter, which outputs Slag alongside Steel or Glass. If either building idles with its inputs available, check the Slag slot before anything else.
Tool shortages and Slag surpluses often appear together. Adding a second Toolsmith doubles the Slag problem unless the first one already has somewhere to send its waste.
Why a full Slag slot stops the main product
A building only starts a task when it has room for every output, including by-products. A Metal Smelter with full Slag storage cannot produce Steel even if Soot, Power and ore are all waiting. The warning is easy to misread as a Steel shortage.
Our by-products guide covers the same rule for Soot, Wood Waste and Sludge. Slag is singled out here because it shows up in the mid-game metal chain, when players start scaling production.
Turning Slag into Fuel
Community guides describe the Fuel Plant as taking Slag as an input and producing Fuel. They also note that it creates Goo as its own by-product, so the Fuel Plant can stall in exactly the same way once Goo or Fuel fills up.
Unlock conditions and exact ratios differ between fan sites, and we could not confirm them on an official page. Open the building’s Work tab in your game to read the live recipe before planning around specific numbers.
Storage is a buffer, not a solution
Storage Sheds can be allocated in batches of 20, with 80 total capacity per shed. Allocating space to Slag lets workers clear the producer and gives production time to resume. If no building consumes Slag, every shed eventually fills and the stop returns.
Place the shed so Peeps can reach both the producer and the consumer. Toxic tiles block ordinary workers, so check the pollution overlay if deliveries stay stuck.
Do Cleaners deal with Slag?
No. According to the official Pollution page, Cleaners consume Soot (or Chemicals) to treat polluted ground. They are not a way to dispose of Slag. Treat pollution and the Slag backlog as two separate jobs.
Sources & research scope
Game information on this page comes from the sources recorded in the dated research. Publisher-hosted wiki entries are community-maintained, and review judgments remain attributed to their writers. Planning advice applies those documented systems and does not claim personal playtesting.
- Wood — Beyond These Stars Official WikiToolsmith output includes Tools and Slag. Checked October 20, 2026; publisher-hosted community documentation.
- Pollution — Beyond These Stars Official WikiCleaners consume Soot to treat pollution. Checked October 20, 2026.
- Beyond These Stars Resources — community guideMetal Smelter Slag output and Fuel Plant processing Slag into Fuel with Goo. Checked October 22, 2026; unofficial.