Shop Talk

When Good Art Materials Go Bad

Do you know when your art materials expire? Do you know which binding agent in which paint develops mold? Most art supplies last years, even decades, if they’re stored in cool, dry, airtight containers. But not all of them. If you don’t treat them well, they won’t reward you with years of mileage. This article is a list of handy tips and tricks so you can know when your good art materials begin to go bad, and how to get the most out of your paints, charcoal, and more.

Please let us know in the comments below any experiences you’ve had with art supplies expiring or reaching their used by date, and add to the list if any other materials come to mind.

"Worn and Stained" by James McKenzie

Oil Paint

Oil paints are one of the longest lasting art materials around. They could have a shelf life of 30 to 40 years, depending on their makeup and the conditions under which they’re stored. For oil paints that have been newly made, you can expect them to survive beautifully if you keep them air tight and dry in a cool, dark place. Avoid changes in temperature and light and keep their tubes clean to avoid damage.

Older oil paint was made with lead in it, so be aware of exposing yourself to deadly, dangerous poison. Shades of white oil paint such as Flake White or Cremnitz White commonly contain lead (but are often sold in tins with warnings) so check your whites and discard any dodgy old lead-based ones.

Over time the oil will split from the pigment, degrading the quality of the paint, meaning in years you’ll eventually have to make a call about the standard of paint you’re willing to use and replace it if necessary.

Shelf life: 30 – 40 years

Look out for: Lead. Be very careful with this toxic chemical. Watch for oil and pigment separating and chuck out paint that has been compromised by this splitting.

Be sure to always discard paint safely and check if it’s okay to add to your local landfill before doing so.

"Pencils are Individuals too" by Simon Greening


Putting an expiration date on pencils is difficult, as the one indicator that they’re messed up is impossible to see. If the lead on the inside of the pencil is broken, they won’t last especially long and when you try to sharpen that piece you’ll have to deal with major breakage and a degradation.

Pencils usually break on the inside when you drop them. They’re quite sensitive, like complex little people really. Because of the (usually wood) casing around pencils, any of this breakage is invisible. Try your hardest to never drop them or inflict force on them so you don’t run into this problem.

One solution is to sharpen them when you come across a broken lead. Learn how to sharpen a pencil properly with a razor blade, not a circular sharpener for more control over the lead of the pencil and a finer point. Store them in a cool, dry place, and, it cannot be reiterated enough: don’t drop your pencils as it’s only a downhill ride towards death for your poor lil lead from there.

Shelf life: It depends entirely on how much trauma they endure. Be gentle.

Look out for: Broken, snapped and cracked leads.

"watercolor 4541902" by calimero


Over time, watercolors separate the pigment from its own binding agent, a natural sap called gum arabic from the Acacia family of trees. When gum arabic distances itself from the watercolor pigment, tubes often go terribly hard and you have to get quite creative with some DIY re-hydrating techniques.

Some artists believe watercolors never actually go bad, but I tend to disagree. There is a time when the gum arabic and pigment have split to a point that is irreparable. If you have hard, cracked watercolors, you can cut them open with a scalpel knife and add water and powdered gum arabic to re-wet, pour, and re-set them yourself. This means their expiry is potentially infinite, but it’s a time consuming process that usually ends in lower-quality paint.

Keep all your watercolors airtight, dry, and clean and don’t stuff water/wetting agents directly back down into tubes of paint as it won’t rehydrate them evenly.

Shelf life: 2 – 3 years depending on your binding agent, could potentially last for 10-15 years if you want to re-hydrate the paint yourself.

Look out for: Split watercolors, usually in the form of separated gum arabic.

"Art" by vaskoni


When gouache is mixed with oxygen it’s common for a slight mold to develop often inside the tube, which is gross and unfortunate. Bleed Proof White is the most common Gouache to develop mold. Some artists add honey to gouache to deter mold developing in any acrylic-based paints and to add texture and ease-of-spread.

Other artists add glycerin to their gouache, which won’t extend the drying time, but it will keep the gouache sticky for longer. Adding a few drops of Ammonia can often help with moldy gouache as well.

It’s important to make sure your caps are screwed on tightly and kept dry. Keep the seal where the cap comes on and off in good condition for a few great years of gouache.

Shelf life: 2 years, depending on mold development.

Look out for: Mold, fungus, and bacteria.

"The Path of Least Resistance" by Barb Baetz

Acrylic Paint

Like gouache, acrylics run the same risk of developing mold and drying out. Acrylic paint is a synthetic-based material so it can’t “expire” like a piece of organic matter can. That being said, in terms of materials that will most noticeably become un-useable, Acrylics are big offenders and dry out very fast. It depends on the quality of the paint and you really do get what you pay for with Acrylics. Try and buy good, “artist quality acrylics, not “student quality” paints. Keep them very dry and use them quickly. You can buy mediums to assist with the wetness of the paint such as acrylic wetting agents and mixers which can help resuscitate dried paint.

An easy way to tell if gouache or acrylics have gone bad is to smell them. They often develop a sour, mildew stench when they’re past their prime. They may still be useable, but you can tell they’re on their way out when they start to smell sour and off.

Shelf life: 2-5 years, until they start to smell sour or dry.

Look out for: Mold and an stinky milk smell.

"Time" by Melissa Taylor

Charcoal & Graphite

Great news! Charcoal, graphite and similar mineral-based drawing materials don’t have a expiration dates. They only become compromised if they’re crushed or wet, so keep them well and they will remain intact forever. Both materials age beautifully and don’t crumble or break apart over the years. BPA free, non-toxic plastic storage containers are perfect for storing charcoal and graphite.

Shelf life: Forever! Just keep them cool and dry.

Look out for: Water, moldy environments when storing charcoal or graphite.

"Day 283 - 18th April 2012" by petegrev

Do you have any tips and tricks for preserving your materials? Please share in the comments below, we’d love to hear your suggestions.