I've got some Mac minis ranging from 2011 models to 2014 models, which I wish to sell. My concern is with the integrity / security of the data on them.
I don't have a large external HD / server to dump all the data onto, so my plan was to take out and keep the HDDs from each Mac mini, and put in a brand new SSD prior to sale.
Other than doing the above, is there any steps I should taken to ensure integrity / security of the data? E.g. will anything be saved to the RAM or CPU / GPU or other components?