adding new paint to old - shelf-life, contamination?

i have read about topping off paint cakes that are getting low with new paint, or replacing sections of split cakes with new strips, which makes me wonder - isn't there a suggested expiration date for face paints, so if you kept adding to a cake, you'd have a range of paint "ages"?

also, since the surface layer gets exposed to the brushes and water, which have touched people's skin, isn't there a chance of mixing "contaminants" (skin oils and cells, bacteria, stuff in the water, stuff floating around in the air, etc) deeper into the cake?

I haven't worried about it - the minute you touch the new paint with a brush it will be in the same state.

As long as your "old" paint is completely dried out, and has been used in a sanitary manner, you'll be fine.

I will dig out the old paint to place on top of the new though, just to keep the rotation going.

And some brands do have a "best before" date - once opened. Frankly, I go through stuff fast enough it isn't a problem.

thanks shannon, and good idea about putting old paint on top of new, i'll do that.

i too put the old on top of the new for rotation sake...plus no one wants to waste these awesome colors. if i don't put it on top of the new, i use the old to make ones strokes and splits, and ive ended up with some really cool ones.

Ah...but never never dig out the old ancient old wolfe white and use it up on some runny nosed little stinker...

yeah, i now have several "ages" of paint, plus new gem powders and eye shadows.  probably going to make some split cakes of the older face paints, and get a new small pallette of wolfe paint to mix with the powders, which i find works well.

looked up the ingredients in mehron mixing liquid. it includes a small percentage of acrylates, which can cause contact dermatitis allergic reaction in liquid form, so i may not get that.

iv'e heard about the legendary old wolfe white, lol, only for you best customers.

If you are concerned about using Mixing Liquid then you may want to steer clear of a good many makeup products including but not limited to fixing sprays, setting sprays and liquids, hair sprays, body adhesives, and most anything in liquid and cake or pressed powder form.

Reactions are almost null, with the percentage used in makeup products so low as to not cause adverse reactions. So low that so many cosmetics have this in some form. It works as a binder, suspension agent, helps viscosity, adhesion, absorption, helps create films, and as a stabilizer.

Somebody is allergic to something!

i was looking up the ingredients in the mixing liquid, as i have a science background and like to know about the safety and properties of things i may put on a little kid's face . i saw acrylates, so i looked up what they were, since it sounded like acrylic, and like it might be one of the ingredients in the cheaper "face paints" that everyone mentions cause irritation.

the description said they are plastic type materials, and are also used in a variety of non-cosmetic products like paints, etc.

but what gave me pause was that acrylates were labeled contact allergen of the year in 2012 by dermatologists. there are quite a number of articles about this issue.  

in addition, the mehron gem powders i got are not colors i would use alone, the garnet is not pink enough and the sapphire and emerald are dark, so i experimented with mixing them with various colors of diluted face paint and got some really nice sparkly shades of different colors. so that's probably the way i'll go.