Material left on a surface after water or another liquid evaporates and its nonvolatile constituents remain.
GlassRenu email archive — publication credit pending
Meaning and boundaries
Evaporation residue describes how material was left behind, not its exact chemistry or whether it is easily removable.
Why it matters in glass restoration
Droplet outlines, runoff paths, and repeated wet-dry cycles can reveal the source and growth pattern of a deposit.