The other day Mark and I picked up a couple of old Purex bottles and of course they were disgusting inside and of course the openings are too small to get a scrubber inside.
After thinking about it for a bit we came up with a solution that worked beautifully. We poured about a quarter cup of steel slag (used for sand blasting), some water and a dot of soap and swooshed...and swooshed. All clean.
Now the question is - would people prefer to buy them filthy and we should not have cleaned them?