Back in the 80's I had a nice HO layout, Lshaped 5x10 and a raised 4x8. I had 2 engines that smoked. The fluid at the time was purple Bachmann smoke fluid. After 5 years I had to tear it down and got out of the hobby. A couple years ago I retired and set up a modest O-gauge and a modest HO lay out. Not knowing that Bachmann had changed their formula I ran the purple fluid in both layouts. Finally ran low on the purple stuff and bought their new stuff. Now none of my engines smoke anymore O or HO. I mixed what was left of the old with the new in a test tube, the purple stuff flaots on top of the new stuff. Any idea how to clear/clean my smoke units, I never ran any engines dry.