Use the exact reviewed booklet
This reference read Breville's official BES870 Series USCM-M21 instruction booklet, including printed Care & Cleaning pages 23 and 24. It explicitly describes the cleaning cycle as back-flushing and separates it from descaling. That is a model-and-version-specific source relationship. It is not transferred to Bambino, another Breville model, another region or every machine carrying a similar light label.
Keep the two tasks distinct
The booklet associates a flashing CLEAN/DESCALEindication with its cleaning-cycle section and a solid indication with its descaling section. The chemical, placement and machine program are not interchangeable merely because one indicator label names both tasks. The site's finder uses that distinction to explain the selected product category. It does not run a machine, diagnose a light or guarantee that a reader's exact hardware and booklet revision are the same.
Do not infer E31 approval from a tablet instruction
The manual's reference to a cleaning tablet does not name or independently approve the selected 2 gE31 product in this reviewed record. Likewise, its descaling section specifically names Breville descaling powder rather than the selected commercial 900 gDezcaljar. The tool therefore reports exact chemical authorization unresolved. A generic cleaner page or a retailer's broad compatibility statement does not override the device source.
Ask a precise follow-up before buying for use
Provide the machine's actual model designation, region and relevant manual version to the equipment maker when resolving a chemical question. No serial number or photo upload is requested by this website. Keep the answer tied to the exact product and task. The reference can help identify the missing decision, but it does not supply a replacement ratio, button sequence or workaround where approval remains unverified.
A different booklet is a meaningful boundary
A reader with a different indicator label or a differently dated regional booklet should not combine the reviewed USCM-M21 description with another source's button sequence. The finder does not offer a merged procedure. It shows which task distinction was actually read and leaves the reader's unreviewed version unresolved. A useful support question includes the exact designation and the relevant instruction, without uploading a serial number here. This keeps a narrow model reference useful while avoiding a brand-wide rule that could be wrong for another machine with a similar appearance or product name.
Sources & scope
Checked November 4, 2026. Manufacturer and retailer references support the specific statements. Dated displayed prices are not final checkout quotes, performance rankings or performance testing. This shopping reference does not replace the exact product label or qualified individual advice. Current received labels, exact chemical/model authorization and independent chemical/equipment/content/commerce review remain pending.
Breville BES870 USCM-M21 official instruction booklet ↗
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