Yes. You can delete the previews, and any smart previews.  It is under the Library->Previews menu.

You can start by just selecting the photos you don't need to work on, and delete the previews for them. Note that LR will rebuild them as needed, like if you re-edit an older photo.

You want to keep previews for the photos you are currently looking at and editing.

Is there a way to get them out of there? I have Lightroom CC btw, not sure if that changes anything.

I think your previews are all stored in there.

https://helpx.adobe.com/ca/lightroom-classic/kb/optimize-performance-lightroom.html#:\~:text=it's%20too%20large.-,Keep%20the%20catalog%20and%20preview%20cache%20in%20the%20same%20folder,lrcat.

Select your photos then Library > Previews > Discard 1:1 Previews. Also may want to check your settings and have them automatically delete the 1:1 after a certain period of time.

First make sure you do not check "Store a copy of all smart previews" and "store a copy of originals" enabled in Preferences-> local storage. Then hit "clear cache". If this doesn't help reclaim space and if your library has synced completely to the cloud (hit the cloud icon in the top right and check whether it say "synced and backed up") , the simplest way to reclaim the space is to quit Lightroom cloudy, delete the Lightroom Library.lrlibrary file (just drag it in the trash and empty the trash) and restart Lightroom cloudy and it will simply recreate the library and previews from the cloud.

In Lr preferences set it to store a copy of all original (full res) files on a folder on an external disk. This disk must have enough space to store all your cloud files. Lr will move any full res files from inside Lightroom Library.lrlibrary to that location and will download the rest from the cloud. Then Lightroom Library.lrlibrary will hold only the info and edits of the files along with some smaller previews — which will free a lot of space in your internal disk. You will need to have this external disk attached when using Lr. All new photos that you add to Lr will be also stored on this folder. I say “also” because, as far as Lr is concerned, the main storage of your files is the cloud. What you have on your devices are just local copies of your cloud files. Normally, as your system is set currently, Lr should dynamically manage the space on your internal drive. That means that the (full res) photos you add to Lr (from some external location) are always copied to Lightroom Library

My Lightroom Library (a file called Lightroom Library.lrlibrary) has ballooned out of control. It now takes up 316.24 GB on a 500 GB Mac. I changed the preference setting so that Lightroom only takes up 5% of my cache instead of 25%, but this has made no difference. I back up all my photos on an external hard drive and don't need them saved locally on my computer. But I'm thinking maybe the originals are somehow being backed up in "Lightroom Library.lrlibrary." How can I get this file size down without getting rid of the edit files attached to my images? Thanks for any thoughts on this!

Help! Lightroom Library Too Big on Mac