from SGW thread
Park CleanUp is a program design to optimize your RCT3 savegames. Park CleanUp analyses your park-files and deletes unused data out of these files. Unused data can be seen as data which RCT3 saves to your parkfile, like references to installed scenery, but which isn't used when RCT3 loads your park again. The benefits of optimized savegames are a
decreased chance of crashes and
optimized park-files will load faster.
In some case this tool has been found to repair corrupted park-files. The best result of this tool are achieved when many custom objects are installed (the original idea behind this program was especially meant for optimizing park-files containing many custom tracks cause these eat alot of space which can cause RCT3 to crash).
Included in the download are the program as well as a user manual (English and Dutch) and a tutorial (English and Dutch). It doesn't matter in which version of RCT3 your savegame is saved.