I clearly remember doing chromatography for the first time at school in year 7, more than 30 years ago. I asked the teacher for extra paper so I could do more at home. More recently I organised a chromatography activity for a mixed-age group of friends' children during our annual Youth Hostel meet-up. They loved it. And I love it when they get to year 7 and tell me they did it again at school! Never underestimate the power of exciting and/or colourful practicals to inspire. I would definitely try the salt solutions if I were doing it again, thanks for the suggestion.