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Oust
Oust Powerful All-Purpose Descaler, 3 Sachets x 6 (18 Sachets Total)
Single-dose liquid descaler sachets for kettles, irons, coffee machines and shower heads. The listing gives a 6-minute contact time, two sachets for heavy scale, and descaling every 3 months in hard water areas. This listing is a multipack of six 3-sachet packs.
Updated October 10, 2026
- Each pack holds 3 treatment sachets; this listing is 6 packs, 18 sachets in total.
- Kettle directions: half fill, boil, unplug, stand in an empty sink, add one sachet and leave 6 minutes (listing).
- Use 2 sachets for heavy scale; if scale remains, reheat until it fizzes but do not boil (listing).
- Suggested frequency: every 3 months in hard water areas, every 6 months in soft water areas (listing).
- Ingredients listed as lactic acid, aqua, sulfate and chloride; made by Henkel (listing).
Good for
People who descale occasionally and want a pre-measured dose with no bottle to pour or store.
Skip it if
Anyone whose kettle maker forbids reheating a descaler, or who descales monthly and wants the lowest number of packs to buy.
Our take
On this page
Our verdict
Oust sachets suit occasional descaling: tear one open, pour it into a just-boiled, unplugged kettle standing in an empty sink, wait 6 minutes, then pour away, rinse with cold water, boil fresh water and rinse again. That is the method on the Amazon.co.uk listing, which also says to use two sachets for heavy scale. One step differs from Dualit's kettle sheet: if scale remains, the Oust directions allow reheating the solution until it fizzes, without boiling. If your kettle manual says never to heat a descaler, do not. We could not open Oust's own website, and pack wording can change between batches, so treat the directions printed on your sachet as the final word. The variant trap: this listing is a multipack of 18 sachets; single 3-sachet packs are also sold.
Safety
The listing names lactic acid as the active ingredient. Wear gloves, keep the sachets out of reach of children, and rinse the kettle thoroughly so no residue is left. Electrical Safety First advises using only products designed for descaling inside a kettle.
FAQ
How long should I leave it in the kettle?
The listing says 6 minutes, with two sachets for heavy scale. If the sachet you receive prints a different time, follow the sachet.
Can I use it on a shower head?
The listing says the sachets suit kettles, irons, coffee machines and shower heads. Follow the directions for each appliance on the pack.
How we researched this
We read the Amazon.co.uk listing, including its directions and ingredients, and Electrical Safety First's kettle advice on 2026-10-10. Oust's own website could not be opened when we checked. We did not use the product.
