I have a bunch of little oil rigs around that size and what I find works best is to fill them with boiling water, I use the kettle for easy pouring, let it soak until the glass is too hot to hold comfortably, dump the water, add iso and then shake shake shake until clean. I then rinse with water to get all the iso out. If I want it super clear I rinse with vinegar, let it dry, and then rinse with water.

If the hot iso isn’t doing it by itself I’d add a good bit of salt after dumping the hot water out and then add iso and shake.

Edit: if you want good reclaim use everclear or another high proof drinking etoh to clean it and reuse the same etoh until it looks dark enough. This is very subjective. You can try an evap from there but without a vacuum chamber you’ll get gooey oil. I just drink mine when it gets dark. You can also cook it down to like 10 ml and have a tincture if you don’t want to drink shots of everclear.