Calculators E-Waste Calculators are also considered Household Hazardous Waste. If your calculator is in good condition, consider donating it. Never Throw in the Trash Calculators contain metals that are hazardous if disposed of improperly, so don’t throw them in the trash. Ways to Reduce Use Your Smartphone’s Calculator If you have a smartphone, consider the calculator application for basic arithmetic instead of buying another calculator. Most computers also come with a simple calculator, and you can download graphing applications for free.