Hybrid Canvas Cleaner Suggestions?

[RamsFan1]

While camping up in the mountains this summer, we developed these yellow spots on the canvas on our hybrid (I have attempted to load pictures, not sure if they will be too large).

I cannot figure out what they are. They seemed to develop while the bunks were open. There were trees around but I am not sure it is sap. I don't think it is mold. Any ideas?

Searching for ideas on the forum, I have used soapy water, Oxyclean (w/o bleach) and Moldex to try to get them clean. None made any difference.

Please send me any suggestions or thoughts on what it may be and/or how to clean it.

Thanks in advance!

[bikendan]

That's why we always recommend PUGs or the generic 5x7 all weather/sportsmen blankets.

Once you get the canvas clean, you really should get some.
Our Roo's canvas is 9 years old and still looks really good because we use PUGs.