Many assume freezing ruins the SCR (exhaust cleanup) supply, but it remains usable. It expands when frozen, so leave headspace in storage containers. Do not add antifreeze; systems warm and circulate the contents after start. Small metal ions from brass or copper can trigger fast decomposition. Use only stainless or approved plastics for funnels, pumps, and caps. Tiny tap-water dilution can raise alkalinity and form stubborn deposits. These deposits often block dosing nozzles and upset sensor readings. Keep containers sealed; air exposure invites CO2 uptake and quality drift. Nordic stop‑and‑go driving benefits from clean dosing and steady spray patterns. For steady performance, use sealed, compliant fluid such as AdBlue.