Hate to say, but these things are not made with quality or longevity in mind.
People have already offered good advice here. If getting a new SD card from a more reputable manufacturer isn't feasible, I'd suggest trying to borrow one to see if that works. You can also try using it on a friends TV and seeing if that changes things.
As far as cleaning goes, 99% isopropyl alcohol in liquid form is what you want if you'd like to try that. 90+% is okay in a pinch, do not use 70%, or anything that simply contains alcohol.
If you have an old computer lying around by chance, I'd also be happy to walk you through turning that into an emulation machine. Something I've been doing for friends and projects for quite a while.