Dataflow Incremental refresh

Hi,

We have set up several incremental dataflows each holding 2 years of historic data and with detect changes enabled.

Occassionally some of the historic records get "hard deleted" from the source system and I would like to make absolutely sure they're deleted from the data flow as well. Was thinking of carrying out a "full refresh" of the incremental load every 4 weeks and scheduling it to run overnight.

I couldn't find an obvious way of doing this automatically but what's the best way to clear out an Incremental dataflow and reload it again ? I didn't want to switch to Full load all the time for a number of reasons.