In a dim corner, behind a limp lace doily, I found it: a large lidded jar, opaline glass in dusty rose and off-white. Stevens & Williams, Alabaster series. Quite the pedigree for something intended to hold biscuits.
It sat there smugly under its dust, as if aware it was rather too fine for the job. Still, I bought it. One does not often find a jar that makes ginger snaps look underdressed.