Well, the reason I ask is I'm getting my eternabond delivered tomorrow and wanted to get a good seal. I don't think that using Murphy's soap would be a good thing for this particular application
Here is Alpha's cleaning guide. I spoke with them by phone when I first got my trailer and customer service suggested Murphy's Oil Soap as it leaves a little oil behind to keep the membrane lubricated.
K_and_I 2011 Rockwood 2604 Nights Camped in 2019: 85 Do we have time for shortcuts?