Ok, gotcha. I have a similar setup in terms of reading a large number of projects, but mine is attaching data versus removing data. I just did a quick draft, so my recco would be:
1. Set up a search module to look up projects that have an entry date of 30+ days (or documents belong to projects of more than 30+ days to get a tighter filter)
2. Depending on the # of projects (if more than 2000+), you'll most likely need to do this using pagination, so you'll need to set up a repeater module
3. Then use the read record + delete record modules (put filters to only pass through to delete if the file type matches X,Y,Z)
4. Set this to run as often as you need - I'd probably suggest once a week, but up to you
