Oh yay! Thank you, Maria! I'm excited about it and glad my mug is coming out well. xD

The "Grain of salt" phrase is suggesting that the use of one grain of salt isn't enough to do anything with and comes from a period where salt was mainly used in the preservation of meats rather than the seasoning of it... but because it was so useful in that means it was very expensive. In essence the phrase is suggesting that you might consider whatever it is before you are preserving for thought before you cover the rest of it in precious salt. : )