How can I get my whites back to being white?!

A common question that is asked is for tips on how to get white clothes/fabrics back to white (they can often go grey/yellow, maybe something to do with the water?). Some suggestions from mums are:

• Use Persil Power Gel - it really does work!! Expensive but worth it.......
• 2 table spoons of baking powder will do the job. I personally would never use clorox cause it turned my whites yellowish
• I put a bit of bleach in the washer while it is filling up and then soap and swish it around.
• White vinegar also helps
• Never used clorox after while the white changes to yellow use backing whote hard soap u can find it on supermarket
• Clorox or vanish
• Pop a capful of neat bleach in your water.
• Vanish spray. I put my whites in the sink and spray the whole thing and keep doing it to all whites then put in washong machine or alternatively put in a bucket with bleach and water and soak for a few minutes and that shud work too.
• Vanish really helped.
• Reduce the temperature of the water used for a longer term solution.

Thanks for the information Kristina - I'll add it to the original post