Typically clean URLs use rewrite rules to select which script (if any) to run, rather than putting the name of the script in the URL.
In the first case, a better response is to return a 301 Moved Permanently response, which can be configured in most server configuration files, or through URL rewriting; in the second case, a 410 Gone should be returned.
engine | V8 engine | steam engine | Thomas the Tank Engine | V12 engine | Diesel engine | jet engine | diesel engine | Web search engine | Internal combustion engine | radial engine | V10 engine | Kawasaki Heavy Industries Motorcycle & Engine | Stirling engine | internal combustion engine | aircraft engine | V6 engine | rotary engine | Game engine | Engine | Two-stroke engine | Steam engine | Search engine optimization | Jet engine | game engine | Ford Cologne V6 engine | Allison Engine Company | Wankel engine | V-twin engine | The Difference Engine |