Green sludge on PCB

Hi all, for a long time the screen on my iMac 27" 2010 model has been turning off randomly if I turn the brightness up, so I opened it up thinking it may be to do with dust buildup, but then I came across some green sludge like substance on the black PCB:

Block Image

Anyone know what this might be, is it the cause of my problem, and possibly how to fix it? Thank you in advance!

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crwdns2934109:0crwdne2934109:0

crwdns2889612:0crwdne2889612:0 0

crwdns2942205:01crwdne2942205:0:

Edit: I have since found out that this component is the power supply of the machine, is it advisable to clean the corrosion off it, or just replace it?

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crwdns2934285:0crwdne2934285:0