You are reading a single comment by @Gordon and its replies.
Click here to read the full conversation.
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
@Gordon
Hmm - that greyness does look like a bit of corrosion - maybe try going over it with a toothbrush?
However that black PCB is the heart rate sensor - it's not very important. The one you'll really care about is what happens if you peel up the button PCB and 'unwrap' that whole black flex PCB, then try and get the PCB+LCD out from the black plastic 'puck'. On the back of the LCD there's the main processor PCB and that's the one that it'll be important to try and get clean.
Sorry to see the seal though - that looks particularly odd. The odd time I've seen them pinched they were flattened, but that one looks like something sharp has almost cut through it and I'm not sure how that could really have happened!