Here is a concise summary of the text:
**Project:** Restoring an old rusty key
**Origin:** Key made in Britain, lost for decades
**Restoration Process:**
1. Disassembly after soaking in water to loosen rust
2. Cleaning of rust using wire brushes, files, and sandpaper
3. Repair of dents and unevenness on the key's surface
4. Smoothing of internal surfaces and hole for the wheel
5. Restoration of the key's adjustment wheel using a drill and sandpaper
6. Cleaning of a small internal spring using orthophosphoric acid
**Outcome:**
* Key restored to functional state
* Surfaces smoothed for comfortable grip
* Original inscription preserved
* Key now fully operational, ready for use. **(Restoration took approximately 4 days)**
Here are the key facts extracted from the text, without opinions, with each fact numbered and in short sentences:
1. The key was likely made many decades ago in Britain, as indicated by an inscription.
2. The key was lost and had become a piece of rusty metal before restoration.
3. Initial cleaning attempts failed due to clogged threads from dirt.
4. Water was used to help loosen the key's ring after 5 minutes.
5. The key was successfully disassembled after the water treatment.
6. The key's thread was found to be in good condition despite rust.
7. A small spring was discovered inside the key's wheel.
8. The key had dents on its edges, possibly from being used to hammer nails.
9. Attempts were made to drive out the dents on an anvil, which partially succeeded.
10. A file was used to process the hole for the wheel, effectively removing nicks.
11. The key consists of two parts, both requiring similar processing for alignment.
12. Sandpaper was used to smooth out unevenness on the key's surface.
13. An angle grinder was used to remove large dents from the key's side parts.
14. Metal shavings from processing can create sparks when scattered over a candle flame.
15. The key was sanded multiple times with progressively finer paper to remove scratches.
16. Orthophosphoric acid was used to gently neutralize rust on the spring.
17. The key adjustment wheel was fixed to a drill using a sushi stick for polishing.
18. The restoration process took at least four days to complete.
19. The spring was soaked in acid to remove rust before reassembly.
20. The key was degreased before final assembly to ensure cleanliness.