Clearing up System Data on Mac mini

We have a Mac mini at our company used for developing Cross Platform Applications. We currently only have two apps in production, so the volume is low. The issue lies with the storage size on our Mac mini. We only have around 10-15 GBs of free storage normally (This creeps up closer to 0 GBs when building and running the apps for debugging). There is over 133 GB of system data, and I was wondering if there is an easy way to clean any of this up? I have searched and searched, but nothing seems to point me in the right direction.

[Edited by Moderator]