Yes Iceman a very real possibility the sticks can and will loosen with the constant heating up and cooling down. I have on occasion too cleaned the slots with a credit card (small slice of one say an inch strip with ROUNDED corners) with a small piece of microweave cloth folded over the end dampened VERY slightly with alcohol and GENTLY wiped along the slot. The same can be done with the sticks just using the microweave cloth over the contacts.
But be VERY gentle when you do that and no need to scrub away just a simple wipe. Use ONLY a lint free cloth such as the glass cleaning microweave type (it is flat surfaced with no fluff to it's surface at all)
This is just an option usually just reseating will do the job so if it is ok now don't worry just keep it in mind