Hi All, Although I haven't posted for a long while, I've certainly been working on my trees. Finally got around to trying to clean some of my unglazed pots in preparation to displaying and just generally to clean up, and used some soapy water followed by rubbing PestOil, which is similar to a white oil / baby oil. (Described here)
http://www.burkesbackyard.com.au/1997/archives/27/in_the_garden/gardening_tips,_books,_techniques_and_tools/new_products__pestoil_and_glykill
The problem is that, often, as soon as the pot dries, the marks appear again. Repeated cleaning has mixed results, sometimes reduces the mineral deposits, sometimes not.
Is this common? Does anyone have a solution to this, whether it's a change in watering or in cleaning? TIA for good advice.