Is it possible to bulk delete message attachments on a Mac?

From the Messages app, I can delete attachments one at a time by right-clicking on them and selecting Delete from the context menu. But I have 1.7G worth of attachments to delete; is there a faster way to do this? Note: this is on a Mac. I did find instructions to do this on an iPhone, but I no longer have an iPhone. Also note: I don't want to just remove them from my computer, I want to free up space on iCloud.