Another interesting discovery is that the source used for the UK '91 or '92 SWE tapes appears not to be that glue party of a 80's home video master.
^ Based on that shot I would've thought it was the PAL equivalent of the JSC/SWE but Russ confirmed it doesn't have the dirty frames seen on that source:
In reel three in the 80's home video master, there is some dirty frames that appears to be caused by some kind of liquid.
"Sorry about the mess."
Docking Bay 94
"...but I've never seen anything to make me believe there's one all-powerful source..."
Also clearly seen in Luke's lightsaber practice scenes after he puts on the helmet. Ejaculation perhaps? ;)
Not in the 80's ITV-broadcast print either. Maybe it was cleaned up for that UK video release but I doubt it.