Comment 3 for bug 1610183

And a short addition
1. Read Arch wiki (hope works for Mint)
   https://wiki.archlinux.org/index.php/Default_applications
   https://wiki.archlinux.org/index.php?title=Desktop_entries&redirect=no

If TL;TR, bind x-scheme-handler/trash MIME type to file manager desktop entry

$ gvfs-mime --set x-scheme-handler/trash exo-file-manager.desktop
where exo-file-manager.desktop is
[Desktop Entry]
Version=1.0
Type=Application
Exec=exo-open --launch FileManager %u
Icon=system-file-manager
StartupNotify=true
Terminal=false
Categories=Utility;X-XFCE;X-Xfce-Toplevel;
OnlyShowIn=XFCE;
X-XFCE-MimeType=inode/directory;x-scheme-handler/trash;
_Name=File Manager
_Comment=Browse the file system

or

$ gvfs-mime --set x-scheme-handler/trash Thunar-url.desktop
Where Thunar-url.desktop is
[Desktop Entry]
Name=Thunar File Manager
Comment=Browse the filesystem with the file manager
GenericName=File Manager
Exec=thunar %u
Icon=Thunar
Terminal=false
StartupNotify=true
Type=Application
Categories=System;Utility;Core;GTK;FileTools;FileManager;