Rema uses cold vulcanizing fluid which is better than rubber cement. That said I find that rubber cement works very well too. As others have said, scuff up the tire with sand paper and allow the cement to dry completely, usu, 10 minutes. Apply the patch and then really work it on. I use a rolling tool that is intended for inserting spline when repairing screen windows. I press hard and roll it over the patch in all directions.