The standard supermarket oven cleaner is sodium hydroxide (lye) in spray form. It works, but it’s caustic enough to require gloves, eye protection, and ventilation, and weak enough that on a really grim oven it just slides off. There’s a better method.
The method
- Cool oven, racks out. Heat-trapping in carbonised grease is what makes most “spray it on a warm oven” methods fail.
- Make a bicarb paste. 200g bicarbonate of soda + ~60ml water. Paste consistency.
- Apply everywhere except heating elements. Door glass inside, racks, walls, floor, roof. Avoid the bare metal of the heating element.
- Leave overnight. 8–12 hours minimum. The bicarb breaks down the long-chain fats over time. There’s no shortcut.
- Scrub off with a damp cloth. Most will lift cleanly. For stubborn spots, spritz with neat white vinegar — the reaction loosens what remains.
- Wipe down with a clean damp microfibre. Two passes minimum to remove all bicarb residue.
What this avoids
No caustic chemicals, no PPE beyond gloves, no ventilation drama. The trade-off is the overnight wait. If you need a same-day result for a tenancy inspection, hire it out — we have ovens cleaned to inspection standard in 90 minutes using stronger but professional products.