Thank you for your feedback! You can try using a lint free rag slightly damp, and gently wipe the surface to remove the dusting. If it's still rough after doing that, you'll want to sand the surface with a 180 or 220 grit sandpaper and make sure it's clean and dry before recoating. Please keep in mind that the surface does need to be heated 24 hours after application to fully cure the coating.
- Rust-Oleum Product Support 3