It’s recommend that the infected file goes to the virus chest so that you make sure that your computer is still working fine without that file and that you may investigate on the infected file. If you delete it then make sure that your computer is still working fine.
By somewhere in the restore folders do you mean recycle bin or in System Volume Information _restore point, etc. where, example (C:\windows\system32\infected-filename.xxx, etc.)?
I would have thought that if it were in one of the system restore folders that it wouldn’t have let you send it to the chest, much less delete it as this area is windows protected storage.
Trojans generally can’t be repaired (either by the VRDB or avast virus cleaner), because the entire content of the file is malware, so it is either move to chest or delete, move to the chest being the best option (first do no harm). When a file is in the chest it can’t do any harm and you can investigate the infected warning.
The caveat to this is if the file has been incorrectly identified as a virus, so never delete until you confirm, generally leave it there for a week or two to ensure it is not an essential file, then think about deletion.