My front curtains were stained BADLY - both inside and out with 'something' that I could not identify. I decided mine were far enough gone that I could not hurt them by machine washing ('standard' type curtains with white 'linen type' liners). I washed them 3 times - they cleaned up nicely except where the stains were. I ended up using a strong solution of OxyClean and a hand brush. I brushed all of the stains on both the curtains and the lines, then washed 3 more times. Took several hours to do the whole job, but I was suprised at how great they look now. They look like NEW except where the liner was torn in one location!
1994 HR Imperial 36W Cummins 8.3/250 (upgraded to 325 HP via TstProducts.com) Allison 3060, PP TPMS, pulling 28' enclosed trailer. Looking for input from other mid 90's HR DP owners.