Just a comment on Nuttelex and it's my personal opinion but I'd avoid Nuttelex like the plague as it and other margarines have been linked in some studies to Macular Degeneration.
Though this is a contentious issue, I believe them - my Mum used it for years (thinking she was doing the right thing for Cholesterol) and now has MD. Never been a smoker in her life (which is one of the main causes of MD). No other history of it in the family.
Maybe a combo of coconut butter and coconut oil would work for the crackles.