I've had mine for almost three years I think and I've always stored them upside down- although it probably doesn't make a huge difference because the foam is so thin. I do find that they tend to dry out very quickly, some colours more so than others, so I bought all the reinkers I could before SU discontinued the craft ink (snifff...) I have been trying in vain to find a good source of empty craft spots that have better-fitting lids than the SU ones.
What I found works best for storing my spots is to keep them in the 'set' boxes they came in, although if you ordered yours singly or discarded the boxes that won't help
I write the names of the colour families on the bottoms of the boxes and keep them in a drawer upside down. The other bonus of keeping them all together in boxes is that it keeps those darn loose lids on!
SU craft ink spots
