How to clear build cache?

I have a very weird problem... whereby WebGL builds contain outdated textures or atlas in a 2D Tilemap object. The textures themselves NO LONGER EXIST and do not show up in Android or Windows builds done via Cloud Build. Local WebGL builds however... these old textures re-appear. The individual PNG images don't exist in /Assets anymore.

I am left to guess there is some remnant atlas or other cached textures lurking in the build process files... And YES, I cleared browser cache and of course even went so far as to delete the files off the server and upload "fresh" ones.

Is there a way to clear out the build cache (if there is such a thing?) in local builds? Is it in /Library ? How do I do this?

 

Here's what it looks like when shows "old" graphics. Some of them arent found and it's just WHITE, while the other part is an old texture that no longer exists.