Hi everyone, i have a similar problem, with stray marks on the edges of bumpers. our team used reversible fabric to construct our bumpers, and there are small sections of the wrong colored fabric on the edges. I put some pictures in this post for clarification.
https://drive.google.com/file/d/0B7V...it?usp=sharing
https://drive.google.com/file/d/0B7V...it?usp=sharing