Canon EOS 5D mark 3 stuck playback button

[rechee]

I just bought a used Canon EOS 5D mark 3 for an absolute bargain price, in a much used condition. Everything works great except the playback button. When I turn on the camera my recent images (the gallery? I don't know how it's called) come up instantly, that was already weird. After this hiccup I can close it and use the camera without a problem, takes images, focuses properly, can open the menu etc. except I can't open the gallery again. I think the button has a contact issue and the camera detects that it is always "pushed in" although it physically works okay. I have/had quite a few canon DSLRs and MILCs and I tried with them if I push the playback button while turning on, they jump right into the gallery. Tried to massage some isopropyl alcohol around the button, but the problem remains. Does anyone have an idea what can I do with it without completley disassembling the camera? Maybe is it possible to pick out the button and clean the contacts? I found out the I can map the gallery to the set button, so I can access it but it would be better to use my muscle memory to access my images.

Thanks in advance

[shadowsports]

Greetings,

I was going to suggest the corner of a business card and working it around the button...  without any cleaners or chemicals.  Seems you've already given that a go without luck.  The contact may very well be bad.  

I don't usually recommend self repair for camera gear.  There is a good tear down on iFIXit for the 5D3 if all else fails.  Used, the camera ranges from $500 to $729 on KEH depending on condition.