SSRS purge rows from dbo.catalog

We have a third party software that generates reports by adding a new "temp" report to the SSRS catalog every time a user prints a report so now the dbo.catalog table is almost 3 GB and has 16K+ rows worth of one time only reports. Is there a way to safely purge these rows from this table? To be clear, I am talking about ReportServer not ReportServerTempDB so EXEC FlushReportFromCache @Path and EXEC CleanExpiredCache are of no help. From what I am reading online Microsoft does not want you messing with this table directly so there is little documentation. I can't find any sort of official maintenance function that works on dbo.catalog. I don't expect many people want to mass delete their reports so this does not surprise me.