Can I brush Permanent Rust Sealer Sprayable Slim?/Can I spray Permanent Rust Sealer Original?

Yes/Yes. Our Sprayable Slim formula is actually our ORIGINAL "original". We sold only this formula for decades before we introduced a version with thickener in it which made it good for brushing. Eventually this thicker formula ended up being called "original" due to its popularity and versatility, and then we later reintroduced the thinner sprayable version and named it "Slim". Customers have brushed on both versions for many years. The thicker "original" ordinarily requires a 10% reduction to spray, but it can indeed be sprayed on. The "Slim" version brushes on, but rolls on with a roller even better. The Slim formula is NOT pre-thinned. The only difference between the two is the original has thickener and the Slim does not. At the end of the day, you'll get the same long lasting results no matter which formula you use. The only difference in how you prefer to apply it.