SqlCeEngine.Shrink Method
Visual Studio 2010
Reclaims wasted space in the SQL Server Compact database by moving empty pages to the end of the file, and then truncating the file.
Namespace: System.Data.SqlServerCe
Assembly: System.Data.SqlServerCe (in System.Data.SqlServerCe.dll)
Unlike the Compact method, the Shrink method does not create a temporary database file. Instead, all empty and unallocated pages are moved to the end of the file and are then truncated, reducing the overall database size.
You can configure a database to automatically shrink by setting the AutoShrink() property on the database.