Blue Crap on things I got

My grandparents were going through their garage and found a Macbook 520 and a TRS80 pocket, but they have this blue plastic like stuff all over the contacts, what is it?

Thanks in advance.

 

Probably copper oxide, which is not a good sign as it shows that dampness is around and it tends to corrode components.

 

Or possibly battery leakage that didn't get cleaned up. Aluminum contacts are very common in electronics and typically don't have a chemical reaction to turn blue (in fireworks I believe aluminum is used to make white). Corroded batteries occasionally do appear blueish.

 

You need to take a photo. Otherwise, we're just speculating.

 

Will get picture ASAP

 

From the contacts on thwe bottom of the TRS-80(had batteries inside, but the battery contacts are fine), and the battery contacts on the battey for the 520.

Sorry about size, and quality for the 1st picture.

 

FeOH.

Its copper thats come into contact with water and has left what appears to be a blue precipitate.

 

Any ideas on removal? I tried to scrape it with a fork, and it does almost nothing.

 

Rubbing alcohol would be a good start. Anything more potent and you run the risk of easily melting the plastic around it.

 

The blue stuff is copper carbonate (and copper sulphate) which is formed after the copper oxidises. Problem is that if it is that bad on the outside then it is likely to have some effect on the inside, if the tracks have been attacked then you probably have a useless machine. You could open the machine to see if you can see any corrosion although the copper can be oxidised under the protective coating so it is hard to see.

Use a copper cleaner (although make sure that it will not melt or damage the plastic) or an weak acid (lemon juice works...) to remove it, use a toothbrush and some elbow grease too. Keep a damp cloth handy nearby. Alcohol is not a acid and won't do a great deal to copper oxides, carbonates or suplhates.

Remember copper sulphate and copper carbonate are poisonous (just to make sure you know) so do not stick you hands near your mouth, wash your hands after handling or cleaning the computer and do not eat or drink whilst cleaning. Do not keep the lemon juice and use it in gin and tonic.

 

Yup. Tastes bad, too!

Yeah, this is certainly a reaction from leaking battery acid. It can cause all sorts of damage, especially if it gets on the PCB.

 

It can also happen to badly stored items that have been wet or damp at some point. Copper that has oxided will generally start to form carboantes after a few years. Remember digging in someones dank basement over some arcade boards and quite a few were showing signs of copper carbonates.