I have a Mac mini (late 2012) which I purchased about a year ago. I installed a SSD 960GB (from an old MacBook) and 8GB RAM. Through theses modifications it has been a really great machine. However, now I am tending to use my MacBook Pro for everything I do and as I use it with an external display I prefer now to have only one machine rather than go between the two. I plan to sell the Mac mini and then use the funds towards a iPad Pro. I am looking for help and a step by step for what I need to do (restore factory settings?) to be able to sell it. I realise I need to back up my data but what would be the next steps? I have read that SSD's are difficult to wipe or rewrite, is this true? The last thing I want to do is to back up all my data and then do something to the SSD causing it not to function. I would like to be able to have Mac OS Sierra downloaded on this Mac mini so it will be set up for the next owner. Is this possible after I have restored it to factory settings. Given the age of the Mac mini I believe the modified ones with a SSD go for a decent price. Many thanks in advance for your help and advice.