PCB etching with household chemicals

Vinegar – Distilled White Vinegar – diluted with water to 5% acidity (Meijer)

Peroxide – 3% solution (Meijer)

Salt – to taste.

Source & how to video: http://www.stephenhobley.com/blog/2011/03/02/still-messing-with-forces-i-dont-understand-the-formula/