How to clean a coffee and tea-stained travel mug?

Only 3 steps to renew your travel mug! Tools you might need are soda powder and a cleaning brush.
Step1: Put into soda powder
Step 2: Pour boiling water over the soda powder and wait for 1 hour
Step 3:Pour the water out and wipe it with the cleaning brush.

For more details about the travel mug please check: https://www.golmate.com/products/mug-tumbler