Why a full by-product slot stops production
The official wiki explains that a building only starts a task when it has room for every output. That includes by-products. A Woodcutter showing a full-storage warning is often full of Wood Waste, not Wood, and resumes only when something takes the waste away.
This mechanic is behind many negative launch reviews. Players describe factories idling with plenty of inputs because Soot or Slag had nowhere to go. Once you check both outputs on every stalled building, most of these stops are easy to diagnose.
Wood Waste: keep it for compost
Woodcutters produce Wood Waste alongside Wood. The Burner Generator can burn it for power, but the official wiki suggests never enabling that option. Wood Waste is needed in large amounts for Compost, which you use to terraform dead ground.
Forests grown on that ground expand the breathable atmosphere and absorb pollution. So Wood Waste ends up feeding the systems that keep Kewa healthy. Place composting and storage close to your Woodcutters early.
Soot: the Burner Generator problem
The Burner Generator produces Soot while making power. As soon as it fills with Soot, the official wiki says, it can no longer produce power. Keep storage close to every generator so Soot is collected before the slot fills.
Community guides note that Soot can feed the steel chain, but one launch reviewer found steel alone was not enough of a sink. If Soot keeps piling up, dedicate a Storage Shed to it, trade it away or hold off on extra generators. A dark town is usually a full Soot slot, not a fuel shortage.
Slag and Sludge
Slag comes from metalworking such as the Toolsmith, and community guides warn that these buildings pollute heavily. Sludge is the fourth by-product on the official Resources page. Both behave like Soot: when the slot is full, the producing building stops.
Place metalworking on barren ground away from homes, with storage beside it. Plan the outlet before you build, because by-products cannot simply be deleted. Community guides note that demolishing a full building drops its contents on the ground as a resource cache.
Storage and trade
A Storage Shed can be set to hold more of one resource, in batches of 20 up to 80 per shed, according to the official wiki. A shed dedicated to one by-product next to its producer is the simplest buffer. Community guides recommend setting by-products to always deliver so they never back up.
Every by-product is tradeable through a Trade Spaceship, Landed Spaceship, Space Port or Warehouse. Trading surplus Soot or Slag clears storage and earns something back. Our storage guide covers shed placement in more detail.
By-products and pollution
Cleaners collect Soot and Slag from the ground, and forests reduce pollution nearby. Ringing early polluters such as the Burner Generator with forest buys time before your first Cleaner. If pollution still shuts buildings down early, one reviewer suggests lowering pollution in the game settings.
Our pollution and Cleaner placement guides explain where to put both. Story Mode adds these systems gradually, which helps on a first run. None of the launch hotfixes changed how by-products work.
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.
- Resources — Beyond These Stars Official WikiLists Slag, Sludge, Soot and Wood Waste as tradeable by-products.
- Storage — Beyond These Stars Official WikiFull by-product slots pause buildings; sheds hold 20 per batch up to 80.
- Burner Generator — Beyond These Stars Official WikiStops producing power when full of Soot; advice on Wood Waste.
- WalkthroughForge: by-products guideCommunity guide: compost, steel chain, resource caches and delivery settings.
- Beyond These Stars on SteamUser reviews describing by-product and pollution problems; checked October 18, 2026.