Woodworkers are a generally thrifty and innovative group of people, and always coming up with ways to save time and money and often use wood to make things that suit their own needs. The one thing I learned the hard way is the lids on metal cans, like paint cans do not always seal 100 percent and if you don't use up what's in them, they can dry out, or even just dry to a point where they have to be thrown out because they cannot be rejuvenated. I learned that you can fix this by using a thin sheet of plastic from a plastic bag to help seal and preserve the contents.
Watch it on Youtube: https://youtu.be/hUOhQVYP2sc
This is how I have managed to keep my only container of wood putty or filler for 20 years or so ... and speaking of wood fillers ...
I have not had good experience with wood fillers, so I try not to use them (as you can see). It's been so long since I have even looked at them, I don't even know what is on the market anymore or how good they are, but here is my past experience with wood fillers.
There are 2 kinds of wood fillers, water-based and petroleum based. I have not found one that takes stains or dyes the same way the wood does, so they are always off color to some degree, then you have to fuss around trying to get the colors to match. Over the years, most woods change color, they often darken, especially woods with more tannin like Oaks. When you have applied any filler to a project, as the wood darkens or changes color over the years, the wood filler does not so in time the wood fillers often standout because they are now a different color than the wood they were originally applied to. Another problem with any fillers I have used, no matter the base, they always dry out, some take longer, but they all dry out and as they sit in wood that is organic and moves and breaths according to the amount of moisture in the air which caused wood movement. Most of these fillers will fall out over time or at least crack because they can't move like the wood does. This creates another problem of wood fillers falling out or creating unsightly cracks (and they are likely discolored now too)
Try Your Own Filler
I have, on occasion made my own wood filler using sawdust, you can't use sawdust from your dust collector or table saw, it's too coarse and it has all sorts of impurities in it that will affect your filler. You need to make your own sawdust with a sander, or my hand that is fine enough to use as a filler. Depending on what you want to use the filler for, you could mix glue with raw, or if you are going to or have stained or dye your project, it's probably a good idea to stain or dye your sawdust before you add glue to it. But TEST, TEST, TEST ... the last thing you want to do is make things worse so always test with some scrap wood to see how your wood filler is performing in terms of color and for sticking to your project. Remember, glue does NOT STICK WELL TO STAINED WOOD. You may need to scrape a bit of stain away from your area, Some stains will not allow glues to stick well to them so know this in advance.
Sometimes our corners don't come together as perfectly as we would like, and in some cases it can be just the saw blade that makes a bit of a wavey line cut. The quick fix for these that can make your corners look perfect is is to "burnish" them, which really just means to slighly round over the edges a wee bit until the wood on each side meets. This doesn't damage the wood in any way or the finish, it simply allows the wood the bend a tiny bit can cover up some minor gaps.
Here's a topic we don\t talk nearly enough about, and that is using plywood for construction of many wood project. Plywood is an excellent product, it\s easy to work with, stable, easy to cut is available in many thicknesses, can be purchased with top veneers of Oak, Maple, Mahogany, Teak and many more. The reason that it can be purchased with different top veneers, is the same reason that it can be edged with the same materials whether you cut them yourself and match them from natural wood, or you can even purchase heat activated veneers that you can "iron on" using a simple household iron, or in some cases the veneers strips come bare and can be glued on. Either way, working with plywood is a great alternative for saving some money and getting wood in wide, stable lenghts for your favorite projects.
Sometimes it hard to remember all the "PRE" things you need to do on a project, like pre-drilling certain things, of sometimes they are ideas that come in after the thought, and like pre-drilling a hole with a countersink, like from the inside of a drawer as an example, is easy to do after you drill the hole, simply reverse the drill bit through the countersink cone and re-attach it to the drill and pulle the cone from the outside and presto, you have countersunk hole that was quick and easy to make.