How to clean your SIM card.

[#1]

It is often suggested that removing the SIM card and battery, cleaning the SIM and putting it all back together will cure a number of faults. Most of this advice is wrong because the problems are often caused by other things, sometimes even the network itself. Quite often the act of restarting the phone, as in this case, will co-coincidently 'cure' the fault. 

However, some faults are caused by the SIM contacts becoming dirty and going dull. Messages such as 'Insert SIM' or 'SIM Not Valid' can be caused by dirty contacts.

One of the best ways to clean your SIM contacts is to use a pencil eraser or rubber. Simply lay the SIM flat on a desk and gently rub the gold coloured SIM contacts with the rubber. You will be amazed how the dull surface becomes brighter. Then blow off the bits of rubber and finally wipe with a dry piece of kitchen towel. Job done!

Don't use an ink eraser as they tend to be too abrasive. This method, which doesn't require any fluid, reduces the chance of damaging the SIM with contaminants.

Doc.

[#2]

Wow, I never even knew this! This is really helpful. I may try this next time I'm having problems.

[#3]

---

doc_rumack wrote:

However, some faults are caused by the SIM contacts becoming dirty or slightly corroded.  

---

the contacts are gold-plated

gold is used because it does not corrode

[#4]

---

andy0 wrote:

the contacts are gold-plated

   gold is used because it does not corrode

---

Of course. A bad choice of expression on my behalf. Perhaps I should just stick with becomes dirty or goes dull. I'll edit appropriately.

Doc.

[#5]

if it doesn't corrode or oxidise, then it doesn't tarnish or go dull

[#6]

how did u find this one out, it is very usefull info.

[#7]

Iv been with giffgaff for a few days and had slow internet even tho my phone was showing the H sign and I tried so meny things to try make the internet faster and nothing worked then I took the battery out cleaned the sim put it back together and the internet started working fast loool I guess it helps some things

[#8]

So dipping it in vinigar as I was told to do is not good then??

[#9]

Sorry but in over 15 years of having mobile phones I've never needed to clean my sim card. If someone is telling you to do this it's because they've ran out of other suggestions. It's like PC support telling you to reboot your computer

[#10]

I work in IT support, and "reboot your computer" is the FIRST thing we suggest, not the last one when we have run out of ideas. Most problems with computers are caused by badly written software causing memory leaks, or things getting corrupted when loaded into memory - a simple reboot is enough to fix anything like this, as it clears and resets the RAM. For any PC problem the first thing to try is always a reboot; if that doesn't fix it, then other things are tried.

I agree on the SIM comment though - the only problem likely to be cured by cleaning a SIM is a "Sim missing" type of message, but the act of cleaning the SIM involves taking the battery out for a minute or two, which gives the phones memory and capacitors time to fully clear and discharge. People think cleaning the SIM has fixed their problem, but it is most likely the shutdown, discharge and restart that has done it.