My mac mini often does memory swapping, because it has 512MB only. I tried to exchange the memory yesterday. If a user want to add his memory, he should ask the apple official service. But, the official service is very high price. If you try to do it yourself, your cost is just the price of the memory module. I searched the method which exchanges the memory in mac mini. Then, I bought a scraper, sandpapers and the 1GB memory module. Two scrapers are good for you. One scraper was not enough for this work.
At first, I reduced the thickness of the scraper with sandpaper, because the scraper was too thick for inserting it to the cover of mac mini. Next, I inserted the scraper to the space between the cover of mac:
I dismounted the cover by using the scraper as a pinch bar.