Hi Rog,
I would be a bit wary of squirting cleaning fluid into the SD Card slot...... Are you experiencing a problem ?? If so, are you sure it is not a faulty SD Card? I've come across a couple in the past ten years or so......
I've never had any 'connection' problems in that area and I am continually changing cards. Many of the SD Card slots which I have seen (cameras, Laptops, SD Reader/Writers etc.) appear to have gold plated contacts - as do the SD Cards - so corrosion is liable to be less of a problem. Also, bear in mind that there is a 'wiping action' on the contacts, every time you insert and remove a card, which should help to keep the contact surfaces free from corrosion.
If you really feel that it is necessary to clean the contacts, you could apply a little switch cleaner to the contacts of the SD Card and insert and remove the card a few times in the KN7000 SD Card slot.
The problem Ray had with the 'phones connection is a bit different since the KN7000 jack socket will not be gold plated and I doubt if his 'phones plug is gold plated ! (although some of the high quality 'phones do have gold plated plugs...)
Unless the 'phones are in continuous use - being plugged in and out - there is liable to be a build up of atmospheric contamination on the jack plug and/or socket.