Some things to consider:
1. Ground yourself with an anti-static wrist band.
2. In used laptops, a substantial amount of the plasticizers (which makes the component plastic') would have boiled off, thereby making the component brittle. Use a plastic scribe and carefully pry apart the parts following the service manual. The parts are brittle!
3. Many of the ribbon connectors are ZIF (zero insertion force) and the latch must be carefully disengaged before separating the connector. This is explained in the manual, but many of us don't read instructions. Hence the term "RTFM"
4. Take photos of the inside of the laptop before disconnecting parts. Use a good camera; not a cell phone.