I spilled a blueberry smoothie on this 2011 Macbook Air that I type on about 10 months ago. I really thought it was over. 
I learned a lot about component level repairs by visiting “Mind the Mac” (in our Repair Directory).
What is component-level repair?
Component-level repair businesses specialise in fault-finding on logic boards and replacing components with functioning (mostly second hand) components for mobiles, tablets and computers. This requires surface-mount soldering, which is possible for amateurs but requires a great deal of practice.
I took in the machine after letting it dry for a couple of days and not attempting to power on again. It’s crucial that users do not attempt to power on devices before bringing them in for repair, or they risk causing greater damage.
• Appearances: don’t judge these businesses by their storefront. The best businesses do not thrive off of walk-in trade. In fact their storefronts mostly serve to receive deliveries, which they get from other less skilled businesses, all over. If you are forced to wait due to numerous deliveries or outgoing parcels, count this as a good sign!
• Warranties: don’t expect too long a warranty. Warranties in this case are to determine whether the reused components they replaced are up to scratch. So they gave me three months, and I’ve had no problems since. (I’ve seen other businesses give up to six.)
• Pricing: expect to pay a bench fee, it takes time to scan and test the board. (That said, some do not charge this fee.) Good businesses basically have a “maximum fee” per model that is economically viable for the owner to pay - and they will let you know when they’ve determined its not viable. They can generally quote you a minimum and a maximum fee. Don’t be afraid to ask questions and make sure you understand. It’s really important to think in terms of cost-per-year in this scenario - how many more years of life might the machine realistically give? If even 1-2 years, it’s often worth it.
Any other tips for those seeking out component-level repairs?