You’re welcome! Wow I forgot about those batteries, they were the worst! That’s an awesome board. I hope you are able to repair it.

Wear gloves and eye protection. Remove that battery and dispose of it in accordance with your local laws.

Gently scrub off and any residual acid with white vinegar and a toothbrush. Brush away or blow off loosened residue until it’s gone, just be aware it’s acid and where you are are sending the particles.

Let it dry. If the rest of the board needs further cleaning you can use isopropyl alcohol to finish it off.

After it’s clean make sure to check for damage before you replace the battery. It’s likely fine, but if it’s been sitting in acid for a while it never hurts to give the board a look over for shorts, cracks, or solder points that lost contact. If it looks good replace the battery and see if she works.

If you decide to disassemble your board to make cleaning easier, I suggest taking a few pictures first. The old MBs don’t have helper notches to ensure parts are placed in the proper orientation and documentation may be hard to come by.

When I worked at an eltronics recycling center (we repaired and resold PCs and printers) we used isopropyl alcohol in spray bottles to clean pc parts. It worked really well. Don’t dunk anything! Just carefully disassemble, spray the part (let the run off fall onto a collection pad), and let it completely dry before reassembly. It may take a few rounds depending on how dirty the part is, resist any temptation to scrub off build up on electrical components. If contaminates absolutely will not come off use a circuit board cleaning “paint brush” with circuit board pcb cleaner to gently clear it or better yet, leave it be. The enemy of good is perfect.

WARNINGS: Wear gloves, eye protection, and a mask. Follow all ESD safety protocols to protect computer parts. If you disassemble the cpu add more thermal paste. DON’T SPRAY THE PSU, if necessary use alcohol on a wash cloth for the PSU exterior. You can speed up dry time by air blowing excess liquid off but be aware this may splatter dirty droplets around the space. Only clean your PC like this in a well ventilated space. Only attempt this if you are comfortable disassembling and reassembling your pc. However long YOU think your computer needs to be fully dry, double that time to be safe.

Also as a bonus. You can put non electric components in the dishwasher. No soap, no heat, as long as they fit and won’t get dinged up by moving dishwasher parts. SERIOUSLY DO NOT HEAT DRY OR WASH ON HIGH HEAT.

I also throw my mechanical keyboards in there but there’s always a chance they won’t work after - so far tho it’s been a success (obviously I make sure they are fully dry before I use them . If you attempt this - at your own risk.