How do I remove grease from Tupperware?

Dawn dishwashing liquid.

Soak it in bleach and dawn dish soap overnight in really hot water.

Wipe dawn on it and rinse

I agree with Dawn dish liquid.

Having a septic tank I will wiped out my pots and pans and Tupperware with Kleenex to get the grease out rather than allow it to go down into my septic system.

Dawn dish soap. Add some white vinegar if need be. I stay away from toxic things like bleach that can actually make some people ill.

After awhile, Tupperware can get that greasy glaze. Some of it can be the breakdown of the plastic, something like the way lecithin from Pam can become baked into your cookware. The easiest effective method to get the greasy coat off that I have found is to hand wash the Tupperware in hot sudsy water, then to dip each piece into a bowl of vinegar. Use a soft dish towel to dry each piece. This almost always works for me. My problem is that I have ancient original Tupperware that we use continually. Some of these pieces were not supposed to be put in the microwave or dishwasher, yet we do both. That stuff is still kind of miraculous! I hope your come clean. Jewell

Bleach Clorox cleanup I use

Here's a post that might help - https://www.hunker.com/13423395/how-to-clean-badly-stained-or-greasy-tupperware-containers

Is the plastic container that you want to remove the grease from a genuine brand name Tupperware product, or another brand?

All plastic food storage containers are not created equally. Unfortunately, some are made from plastic that absorbs grease, making it very difficult to remove entirely.

Soap and water.