Dyes and stains of various kinds can have both a positive and negative connotation.

We seldom have to dye our own cloth these days.  We simply go to a store and choose the colour and shade most appealing to us and the purpose it is intended for.  Gone are the days when we had to dip our hands in a tub of dye, and spend the next week trying to get the stain to go away.  The manufacturer does all that for us now.

Dyes are generally used to create an effect we want.  The same is true of stains used in the making of furniture and other aspects of the woodworker's trade.  They are used to achieve desirable results.

Sometimes, though, dyes or stains can produce effects we do not want.  Red wine spilt on a tablecloth, paint accidentally spilled on a new rug, a favourite shirt stained when a ball-point pen leaks into the pocket.  These are stains we want to avoid.

And then there are the "invisible" stains that are nevertheless very apparent to others - as when our character is stained.  Or when our reputation is spoiled by some word we have spoken or deed we have committed.  These are the stains that leave the most permanent mark.  We can replace a tablecloth, or buy a new shirt, but to restore confidence in our integrity is a much more difficult assignment.