Motherboard in a sink, ready for a shower.

Jon, are you crazy?

Yes I am, but that has nothing to do with PC repair. And this, my dear reader, is the Holy Grail of PC repair: Mud removal.

Now, this process isn’t exclusively for actual mud, but that’s what my new toy had on it. Most often this would be attempted on a board that’s been in a smoker’s possession for most of its life. Or sometimes extremely fine pet hair and dander has become encrusted in every little corner of the board. Essentially any condition for which a vac-n-brush isn’t sufficient.

PC Repair mud motherboard MOBO
My new toy, a discarded MOBO covered in mud and smoke residue.

I got this at the dump, because it was in a case I needed parts of. I never had the intention to use the actual hardware inside the case. But when I started taking it apart I discovered an intact, intergenerational PC.

Since I now had a discarded old computer that may be recoverable, I decided to record the process for you to read. I’ve done this before on a board that had been in an area with very fine dust that had gotten everywhere. But I’ve never done it with a muddy one before, so it’s a fun opportunity for me to do something kind of new.

Before you start

Before you begin the process you’ll want to have all your tools and materials ready. You’ll need screwdrivers appropriate to the screws involved, needle-nose pliers, somewhere to put the screws, and a soft paintbrush. Sometimes you’ll need tweezers for the pin jumpers.

Consumables you’ll need are distilled water and isopropyl alcohol for right now. You’ll need some thermal goop for later when you reassemble the computer. Read more about that in my previous article regarding how to choose a heatsink.

PC Repair alcohol water tools
What you’ll need to do this properly.

The Beginning

First thing to do is make sure the PC in question has been unplugged for at least a week. This allows the capacitors to passively discharge, so they won’t explode when you get them wet. Additionally you should remove the CMOS battery, usually a 2032, as far ahead of time as possible, but at least a full 24 hours.

PC Repair Heatsink mount screws
The heatsink mount, onboard GPU heatsink, and screws.

When you’re ready to begin the wet process, start by removing everything that can be safely removed. This will usually mean the heatsink mounting hardware, front and back, any heatsink mounted directly to the board, and any pin jumpers. You’ll wash all of this stuff separately. Keep the screws grouped by location or type. Protip: You can make a magnetic tray with a flat candy tin and some small disc magnets.

Ideally you could remove the BIOS chip, if it’s an ‘insert’ type, but only if you have the proper claw tool. I don’t, so it stayed in. This just means you’ll have to be extra judicious in this area during the drying phase.

PC Repair BIOS Chip
The BIOS chip in its’ slot.

Now you’ve got all the easily removable stuff off, and you have a bare motherboard. You’ll use the brush to gently remove as much loose debris as will come off with minimum force. Especially with mud or dirt, too much pressure risks dragging sand across the electrical pathways near the surface and damaging them. After that’s complete you can move to a clean sink to begin the wash.

Getting Wet

Using a fairly low pressure of water, gently get the stream into every space possible. Between the capacitors, the I.O. ports, VRMs, into the cable plugs, right up in the CPU socket and RAM slots, and of course the expansion card slots. Leave no space un-sprayed, and take your time. Once you’ve gotten everywhere, take a good few minutes and look for hidden problems.

PC Repair MOBO water sink
*nerds screeching in despair* as I run water over the board

If your MOBO is dirty enough to warrant this process, chances are there’s some corrosion you couldn’t see before. Mine had some minor corrosion on the pins, and one of the resistors for the audio controller. Barring some catastrophic damage, this shouldn’t keep the MOBO from working. However if yours has corrosion on more than a few parts, or on a particularly vital component, that may be more problematic. If you find any corrosion gently pick it off with a very small flat screwdriver, tweezers, and/or a cotton swab. Be mindful not to leave any bits of cotton on the board after this process.

If there’s dirt sticking to components in tight spaces, like between the expansion card slots, use a very soft bottle brush to clear it off. Use this very gently, and avoid the sponge on the end, lest you leave bits of sponge on any sharp edges.

PC Repair MOBO Back
Don’t forget to wash the back, where all the exposed contacts are…

Rinse + Dry

Now you’ve got the thing clean, but it’s still a motherboard covered in tap water. You need to rinse it to remove the inevitable mineral contents of tap water. Now you bring in the distilled water for a thorough rinse, getting into all the little spaces you got the tap water into, to gently chase it out. After that you do the same with isopropyl alcohol.

PC Repair MOBO alcohol
Clean MOBO ready for a night on the town

After the alcohol shower (ideally an alcohol bath if you’ve got that much), you’re ready to dry. There are three options for forced air drying: Canned Air, Low PSI air compressor, or hair dryer on ‘cool’ setting. I have a hair dryer so that’s what I’m using.

PC Repair PCI hair dryer
Using the hair dryer with long end to force alcohol out of the PCI slot

You want to really get in there to force out the alcohol that’s pooled by capillary action. Make sure you keep it on ‘cool’ if you’re using a hair dryer, or you risk boiling it, and melting plastic. You’ll want to do the same for the RAM slots, USB-3 headers, and 24-pin power plugs.

PC repair MOBO CPU slot dryer
Drying out the CPU slot as close as possible.

Take off the lengthwise attachment for the rest, forcing air down through the CPU slot, clusters of capacitors or other tall components, and the BIOS chip slot. If your MOBO has on-board graphics, you’ll need to blow at that from the side to push out the alcohol that’s pooled between the chip and the board itself.

The waiting

Once you’ve cleared the large masses of alcohol, you need to set the board aside to dry. Ideally you’ll hang it up out of the way in a cool, dry space, so it’s hanging vertically. Don’t try to rush this final process. At the very least it’ll need to dry for a week. People have told me they dried it out in the sun for a day and it worked, but I cannot and will not recommend drying it for anything less than a week. Nor do I recommend drying it with heat. In some cases two weeks will be necessary.

PC Repair MOBO hanging up
MOBO hanging up in the PC repair corner of my workshop

So I’ve done that. In a week I’ll reassemble the thing and see if I’ve got a working PC out of it. Even when you do it perfectly, if the board was non-functional for reasons other than the dirt, there’s nothing a cleaning can do about it. Doing an operation like this is a matter of personal priority. I personally hate to see anything usable discarded, especially something like a PC that should really be recycled.

That said, this PC is not top priority. If it doesn’t work, I won’t cry about it, because it was a retrieval from the dump that I only needed case parts from. But if you have an important or valuable PC you need to save this way, I’ll be happy to know this guide helped you.

Keep your eyes open for part 2 in about a week’s time. Ta-Ta.

Shameless nerd, fan of the obscure, over-analyser of everything. You can rely on me for spouting my honest opinion of whatever I’m blathering on about.