As a donator, not only do you have access to the Builder commands, but also the ability to retrieve your previous work from the archives. Guestcity and flatgrass are periodically land wiped to allow guests to continue to build.
Each archive version of each map has its own incremental ID (1, 2, 3 … 159, 160, etc) which contains saves from various points in time. To access any of these, you use the command:
/museum
For example, to access an older version of guestcity, you would say:
/museum guestcity 14
Upon entering this command you will be instantly moved to the archive version. You can build and destroy blocks here, but these changes will not be saved for obvious reasons. To bring your creation from the archives back to the actual map, simply locate your building and use: /copy.
To use /copy, it works the same as /cuboid or /z. You destroy/build a block in one corner then go to the opposing diagonal corner and destory/build a block there. This will copy everything in between the two spots you just chose.
Note: in order to copy everything in terms of height, you need to build/destroy a block on a different level to the other block.
Once copied, return to the map using /goto , type in /paste and click a spot. You’re done!