Cleaning my Seek Outside 6 man

[Ishootprime]

Me and a buddy of mine took a quick overnight down to Lake Jocassee with my 6 man Seek Outside tipi. The tent pads were that really fine almost beach type sand. I got the majority of it off, however, there is still this really fine layer that just will not come off. I have since used it twice in the rain hoping that it would rinse everything off, and I have hand washed in my tub. Still there. Again, not much, but enough that I am a little concerned about it. Called seek outside and they definitely said that it could create problems. Any other ideas about ways to get this clean? Thanks in advance for all the help.

 

[RockChucker30]

Gentle detergent such as woolite and a front loading washing machine on a gentle cycle, or a top loader without an agitator.

The only problem with it being there is abrasion in the bag as the fabric rubs against itself. If it's in storage and not moving it won't be a problem.