Problem: Camera makes nasty grinding noises and displays "E18" on screen when switched on.
Cause:
Sand inside lens unit.
Solution:Disassemble camera and lens unit, clean thoroughly and reassemble.
Equipment needed:
- Electrical screwdrivers
- Cotton buds
- Tweezers
- Torch
- Rubbing alcohol
- Instructions courtesy of Google

Method:
Things start well - the instructions are detailed and the camera seems to be a bit like a lego kit, albeit with tiny screws and lots of circuit boards.

It turns out that almost every screw is different in length, diameter and thread size so we have to devise a way of remembering where every screw came from. Using double-sided tape we stick the screws to little drawings of the various components.

Things start to get quite tricky - the lens unit is right in the middle, attached to every other part and the instructions are for a slightly different model meaning we have to go it alone from here.

3 hours later and the lens unit is finally free from the other parts so it can be dismantled.
This is definitely the hardest part. There are about 30 parts including tiny springs, the shutter unit and little plastic rings on runners. We eventually get the whole thing apart and clean out the sand but it takes so much concentration we forget to take any pictures.

8.5 hours later and it's almost back together, although the long periods of intense concentration and lack of food, water and natural light have taken their toll.

9.5 hours after we began and the camera is finally back together, although not exactly in 1 piece. We have a strange plastic clip, a metal plate thing and 3 screws left over.
We cross our fingers and hit the on button. Amazingly, the E18 error no longer shows. Unfortunately, neither is anything else - it is totally dead. We decide to go for steaks and wine to congratulate ourselves on a job not done.
Conclusion: Leave this sort of thing to the professionals.