That Wilko spray certainly produced an impressive improvement. I know WD40 tend to be a bit secretive about the compositions of their various products. However, where and where available, e.g. to satisfy health & safety regulations, it can be possible to find materials safety data sheets that give a breakdown of the composition. When I did this recently for "ordinary" WD40, it was 25% lubricating oil and 75% a volatile solvent, which acts to help get the oil into tight spots and then evaporates.