When that Breville Barista Express "clean me" light comes on, it's time to descale and clean the machine! Here is my step-by-step process to do it. (This is not an official Breville document, its just what I always do, so follow this at your own risk lol).

You'll Need:
Cleaning tablets & replacement water filters: https://amzn.to/3CDpqLF
White vinegar

HERE ARE MY STEPS:
1. Remove water filter from tank. Throw out old filter.
2. Follow instructions on water tank to replace filter.
3. Leave filter out of tank while cleaning.
4. Fill water tank 50/50 with white vinegar and water.
5. Remove drip tray and portafilter and place large container under grouphead (and a small container under the drip spout underneath to catch drips. 6. Press and hold 1 cup button until half of tank has emptied.
7. Run hot water out of hot water spout until tank is 3/4 empty.
8. Run steam wand for 2 minutes.
9. Refill tank again with 50/50 water and white vinegar. Repeat steps 6-8.
10. Rinse water tank out well with water to get all the vinegar out. Refill with fresh water and repeat steps 6-8 one more time.
11. Put the single cup dual wall basket into the portafilter. (It is written on the bottom of the basket, and the single cup one is the smaller of the two dual wall baskets.)
12. Put the rubber cleaning disc in, then add a cleaning tablet.
13. Put portafilter into the grouped and place the drip tray underneath to collect the soapy water.
14. Turn machine OFF. Make sure there is still w...