Hey there tonifromdeforest,
Thanks for reaching out to Apple Support Communities. I understand you want to clean up your Mac from junk and have a question about removing cache.mov folders to trash. I’ll be happy to help.
I’m someone who likes to periodically go through and clean up the files on Mac as well. With the option to optimize storage in macOS High Sierra, it’s very easy to do but I always suggest having a Time Machine or other backup handy before doing this. Here’s a link with more info:
How to back up your Mac
Once you have a backup, I would say first free up storage and delete files from your Mac using the steps in these links:
How to free up storage space on your Mac
Find and delete files in System Information on Mac
You can find more helpful info on this here:
Optimize storage space in System Information on Mac
I hope this helps.