WD40 is not a penetrating oil - it's
Water
Dispersant and the 40 denotes the number of trial brews 'til it worked OK.
I do the wrap in dispersant soaked rags and leave as long as possible - well I used to when I did my own stuff.
After that it's heat - heat nearly always works but it needs real heat, not a silly wee Halfords Gas Burner thing
