Heat tint
The rainbow or brown bloom on stainless steel that has been heated. Not a deposit and not dirt: the metal's own surface oxide, thickened by heat.
In detail
Stainless steel owes its corrosion resistance to a thin, invisible oxide film. Heat thickens that film, and past a certain thickness it interferes with light and shows as colour — straw, then blue, then brown. That is heat tint, and the reason it resists ordinary cleaning is that there is nothing on top of the metal to remove. The colour IS the surface. The UK stainless trade body is reassuring about the ordinary case and specific about the exception. Heavy heat tinting is 'unlikely to be encountered in normal use', and where it appears on cookware, REPEATED CLEANING WITH NON-SCRATCHING CREAMS should remove burn marks. Its table gives the same route for heating or heavy discolouration: a cream or polish, or a nylon-type pad worked ALONG THE GRAIN on brushed and polished finishes. The exception matters because it is not domestic. For severe cases — the body names welding repair and fire damage — acid pickling pastes and passivation solutions exist, they change the surface appearance, and they are professional treatments.
What works
Mild cream cleanser is effective against Heat tint Supported
Sprint 29. Repeated application rather than a stronger product — the instruction says so.
Sources for this page
Sources
Care and Maintenance of Stainless Steel
British Stainless Steel Association, Stainless Steel Advisory Service, 2001 · Trade or professional body
Relied on for: That heating or heavy discolouration is treated with a non-scratching cream or polish or a nylon-type pad along the grain; that heavy heat tinting is unlikely in normal use and repeated cleaning with non-scratching creams should remove burn marks from cookware; and that nitric and phosphoric acids may be used with care while sulphuric and hydrochloric must not. (states this directly)
Verification: a person has read the passage relied on.
Read on — Sprint 29 re-read all four pages: Factors Affecting Maintenance, Maintenance Programme, Cleaning Methods with the whole of Table 1, Table 2, and Notes 1-10. Earlier sprints named both tables but carried only part of one and none of the notes. Supports a wider statement — our claim was widened. SPRINT 29 FOUND THIS UNDER-EXTRACTED WHILE ALL THREE SIGNALS CALLED IT DONE: zero representation debt, in the fully-harvested list, and honestly noted as 'read in full'. Five of Table 1's eleven rows, all of Table 2 and eight of ten notes had never reached the graph. Newly built: tannin and coffee deposits, heat discolouration, the 1% ammonia routine clearance, oxalic acid for embedded iron, and the condition-triggered domestic frequency rule. The paraphrase cap is part of the cause, and the fix is not a longer paraphrase — the facts belong in the citing records.
Last reviewed by a person on .