No need, any tow truck large enough to tow the motorhome will have their own air supply.
When I was maintaining large diesel generators at transmitter sites, we'd "polish" the fuel every year or two. Essentially it's passing the dirty fuel through a series of filters decreasing in size to remove water, sediment and microbial contaminates. When you're done you have essentially new and fresh diesel. We used a commercial service for our 5000 gallon storage tank but you can DIY for smaller quantities. Google "diesel fuel polishing" for several articles and videos.