Protecting the top

[Sas]

My Owners Manual says that I can use Scotchguard to help protect the top. Having used it before for tents and canvas awnings, I knew to buy the "Outdoor" Scotchguard. However, the Owners Manual also says to prevent overspray onto the rubber seals, painted body sections and the glass. To those of you who have used a spray protectant, other than masking the areas not to be sprayed with masking tape and paper, how did you protect the other areas?