a movable feast

The other day the periodical alarm regarding dyes went off again.It has always annoyed me and the tales about how incredibly toxic MX dyes are have always amazed me. Yet everyone goes about the house happily spraying oven cleaner, window cleaner etc etc. etc without giving them a thought. The reasoning behind the lack of concern might be that as they are household products they are perceived as safe. WRONG! and yes i'm shouting.

Hand in hand with that myth, -excuse me you're not going to eat the powder as a spread or breath into the jar as you judiciously would not breath into any unknown jar, right?-the following go around and around in the ferris wheel of dyeing and they periodically re-surface causing varying degrees of alarm to new dyers and fiber artists.
And now without further delay and not in any specific order here they are, the MoD s - those magnificent myths of dyeing

you should use hot water to dissolve MX dyes.

If you do that what you'll be doing is activating the dye making it react with the water before it can hit the fabric.It means waste of dye and weaker color yield.

MX dyes cannot be used for silk.

Yes, they can be used, provided you use acetic acid as the auxiliary chemical. Colors are as bright as you are able to dye them.

Avoid using soda ash with silk.

This is a half truth. While in strong solutions it may weaken and dull silk, weak solutions do not present problems. In fact silk is scoured using a mild soda ash solution in a number of short baths.

Salt is needed to fix the dye.

Not really.What salt does is reduce the solubility of the dye in water and this favors the adsorption of the dye by the fiber.It also acts as a surfactant by suppressing the negative surface charge on the water so that the dye molecule can move towards the fabric and attach to it. (Knutson.p 51)

Dyes have a shelf life and after that they are useless.

Another half truth. They will probably not work with cellulose fibers, but will perform satisfactorily on silk with acetic acid as the auxiliary chemical. Shelf life depends on the storing conditions, light and humidity. We too have a shelf life.

MX can be used to dye in cold water.

Well, depends what you call cold. They need at least 70ºF(20ºC) to perform optimally as immersion dyeing.below that, you're throwing dye way and wasting your time.
And i will not discuss batching temperatures here as this is a topic all by itself.

Fabric/fibers should be rinsed in hot water.

Not the first rinse. This one removes the salt and chemicals. Then you can rinse the fabric in hot soapy water until it runs clear. The last one -and this is me- should be with Synthrapol just to be sure there's no more unfixed dye.

Natural dyes are greener and eco friendlier. Yes, provided you do not use any mineral salts as mordants. However there's a debate as the amounts and dilutions a home dyer uses will not change the eco system in ages. There's a personal choice here as with most things in life. Yet there's also the issue of toxicity in plants. Not all plants are made equal and being plants is not a synonym of being pretty and friendly. This is my all time favorite myth, seems that not too many have been attacked by a nettle plant :)

And the onions you may ask. Apart from the fact that their skins give beautiful oranges and yellows they also make me cry just like the above.

There is an excellent on line resource all facts as it is kept by a chemist. It's also a labor of love . If you have doubts about dyeing visit Paula Burch's site