Two drain chemistries
UK drain shelves sell sulphuric acid (One Shot-style) or sodium hydroxide gel (Mr Muscle-style). They dissolve grease and hair by opposite mechanisms — and they are not interchangeable.
Sulphuric acid: add to the drain as labelled — never add water to concentrated acid. Caustic soda gel: exothermic when pearls meet water — add pearls to cold water slowly if mixing your own.
Oven gel is weak caustic, not drain strength
Oven Pride and similar cold-oven gels are ~4% NaOH with thickeners so they cling to vertical enamel. Strong enough for baked fat; nowhere near drain gel strength.
Bulk caustic pearls let you mix oven-strength or drain-strength liquor — but you must dose deliberately. See each teardown’s grams-per-litre maths.
PPE and plumbing
Splash goggles and acid-resistant or heavy household gloves for both classes. Ventilation mandatory. Old lead pipes, aluminium fittings and porcelain that you care about may not tolerate strong acid — read the label.
Bleach is a third product
Domestos-style hypochlorite clears organic bowl stains — it is not a drain unblocker and must never meet acid or caustic drain products in the same pipe or bucket.
FAQ
- Can I use One Shot in the oven?
- Absolutely not. One Shot is ~91% sulphuric acid for drains — catastrophic on oven enamel and lethal if mixed with water the wrong way. Oven Pride is ~4% sodium hydroxide gel for cold ovens.
- Is Mr Muscle drain gel the same as Oven Pride?
- Same sodium hydroxide family, vastly different strength. Mr Muscle kitchen drain gel is ~36% NaOH. Oven Pride is ~4%. Never swap them.
- Can I pour drain cleaner then bleach?
- Never. Acid drain cleaner + hypochlorite bleach releases chlorine gas. Caustic + bleach is also dangerous. One product, one application, flush with water, wait before anything else.
More household cleaning guides
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Household acids and alkalis decoded — limescale, rust and never-mix rules
Household guide
Disinfectants decoded: bleach, Dettol and hand gel — hypochlorite vs PCMX vs IPA
Household guide
Carpets and laundry stains: percarbonate vs machine surfactant
Household guide
Washing machines and dishwashers: Calgon, salt, citric and colour-run
Related teardowns
Live stacks this guide points at — mix maths and DIY affiliate links on each page.
Household cleaning
Instant Drain Cleaner
One Shot
- Retail pack
- £18.001 litre
- Raw active
- Sulphuric acid 96% (trade drain strength)7664-93-9
This is not caustic soda gel (Oven Pride is sodium hydroxide). One Shot is ~91% sulphuric acid — a completely different drain chemistry. Trade-strength, corrosive, and labelled ‘never add water’. Bulk 96% sulphuric is the same molecule in a drum; still not a casual consumer product.
Household cleaning
Kitchen Drain Gel
Mr Muscle
- Retail pack
- £4.501 litre
- Raw active
- Sodium hydroxide pearls 99% (caustic soda)1310-73-2
Caustic drain gel — not sulphuric acid (One Shot) and not 4% oven gel (Oven Pride). Mr Muscle Kitchen Drain is ~36% sodium hydroxide in a viscous gel. Caustic soda pearls dissolved thick with salt make the same chemistry; still corrosive, still ‘add to drain, flush later’.
Household cleaning
Complete Oven Cleaning System
Oven Pride
- Retail pack
- £4.00500 millilitres
- Raw active
- Sodium hydroxide pearls 99% (caustic soda)1310-73-2
The bag is theatre. The gel is dilute sodium hydroxide. Caustic soda pearls at about 40 g/L make the same 4% attack on burnt fats. Corrosive — this is not a toy, and it is not a lemon-scented miracle.
Household cleaning
Oven Cleaner
Mr Muscle
- Retail pack
- £3.50300 millilitres
- Raw active
- Sodium hydroxide pearls 99% (caustic soda)1310-73-2
Another caustic gel with marketing. The attack on polymerised fats is sodium hydroxide. Dissolve caustic soda pearls to about 4% w/v and you get the same chemistry without the trigger-bottle tax.
Household cleaning
Domestos Original Thick Bleach
Domestos
- Retail pack
- £2.20750 millilitres
- Raw active
- Household thin bleach (sodium hypochlorite ~5%)7681-52-9
Sodium hypochlorite plus a thickener so it clings to ceramic. Thin household bleach is the same oxidiser without the brand, the dye and the TV campaign. Never mix it with acids or ammonia.
Household cleaning
Original Washing Up Liquid
Fairy
- Retail pack
- £1.25320 ml bottle
- Raw active
- SLES 70% paste (sodium laureth sulphate)68585-34-2
Fairy is mostly water and SLES — the workhorse anionic surfactant in almost every UK washing-up bottle. A 25 kg drum of SLES 70% paste dilutes to hundreds of litres of 2% working liquor. You are paying for the green bottle and the scent, not a proprietary molecule.
DupeStack provides chemical concentration data and educational mixing guides only. Wellness pages compare food supplements, not medicines or prescribed treatments. Always review the supplier Safety Data Sheet (SDS) and comply with UK Health and Safety Executive (HSE) and COSHH regulations when handling concentrated substances. Mixing and storage are at your own risk. Some links are affiliate advertisements (Amazon Associates, eBay Partner Network, and Awin when those programmes are live). Commissions do not change listed concentrations or calculator output.