Some can never return !!!
Be Safe !!!
Sadly, some can never be restored without extensive work and just not worth the trouble. My most recent project is restoring an Eddystone. My parts guy and expert set me up with all "E" designated parts and did some of the most challenging restorations. It's not as "pretty" as when I first got it but it's back to being a classic. .....I definitely would NOT choose to restore a sporterized rifle.
Be Safe !!!