Tupperware should have died with the invention of the microwave. You inevitably want to heat things up in the microwave and grease burns will forever stain the material.
LPT: Always transfer the food you're microwaving from the storage container to a dish. That prevents the problems you mention, plus it helps with reasonable portion sizes.
Alternatively, when storing food, portion it into glass containers that can quickly be microwaved. That's our approach, makes lunches both when working at home and in office easy and we're more likely to actually eat/finish the leftovers before they go bad.
