The honest answer comes in two halves, and they are completely different.
Wet acrylic comes off easily with water. If you have just gone over a line, you have a couple of minutes to fix it properly.
Dried acrylic does not come off, and you should not try. Once acrylic has cured it is an insoluble plastic film bonded to the canvas. Soap and water will not lift it no matter how patiently you scrub, and scrubbing a paint by numbers canvas removes the printed lines and numbers underneath, which turns a small mistake into an unpaintable patch. The fix for dried paint is to cover it, and acrylic is very good at being covered.
If the paint is still wet
Move quickly and gently. You need a soft cloth, cotton swabs, and lukewarm water.
- Blot, do not rub. Lift the excess with a dry cloth first. Rubbing drives paint into the weave and spreads it.
- Use a barely damp cloth. Dip in plain lukewarm water and wring it out well. A soaking cloth pushes water through the canvas and can warp it.
- Work from the outside in. Dab from the edges of the spill toward the middle so you are not enlarging it.
- Cotton swab for tight spots. A damp swab reaches into a small section without touching its neighbors.
- Let it dry fully before repainting. Paint applied onto a damp patch will not sit evenly.
Plain water is enough. A trace of mild soap is fine for a stubborn wet smear, but rinse it with a clean damp cloth afterward, because soap residue left on the surface stops fresh paint gripping.
If the paint has dried
Paint over it. This is not a compromise, it is the correct method, and it is what the medium is designed for.
- Make sure the area is completely dry and flat. If there is a raised ridge or blob, level it first. See below.
- Apply the correct color in two thin coats rather than one thick one. Let the first dry fully, which takes minutes. Two thin coats cover better and will not crack.
- If you are covering a much darker color with a much lighter one, put down a thin coat of white or the palest color in your kit first, let it dry, then apply the correct color over it. Light acrylics are the least opaque, and trying to cover dark blue with pale yellow directly can take five coats.
- Feather the edge so the repair does not sit as a visible patch. Carry the new color a hair over the original boundary rather than stopping exactly on it.
Levelling a thick blob
Let it dry completely, for a day rather than an hour, then gently work at it with a fingernail or the edge of an old plastic card until it is flush with the surrounding surface. Take your time and stop as soon as it is flat.
Do not use a craft knife or a razor blade. The canvas is thin and a blade goes through it far more easily than people expect, and a cut canvas cannot be repaired invisibly.
What not to put on the canvas
Rubbing alcohol, acetone, nail polish remover and paint thinner all appear in advice about removing acrylic. They do soften cured acrylic to a degree. They will also dissolve the printed design and eat into the primer underneath, and none of that is reversible.
On an ordinary canvas that might be a trade worth making. On a paint by numbers canvas it is not, because the printed guide is the entire value of the surface. Remove the numbers and you no longer have a kit, you have a blank canvas with paint on it.
removing paint from a plain canvas is a different question, and on a blank canvas there is far more you can do.
Also avoid: scouring pads, magic erasers and stiff brushes, all of which abrade the print. And avoid soaking the canvas, which loosens it on its frame and can leave a permanent ripple.
If you have already lost some guide lines
It is recoverable. Use the reference print that came with the kit, ours is 11 x 17 so the detail is readable, and redraw the missing boundaries lightly with a soft pencil. Pencil disappears completely under a coat of acrylic.
Avoiding it in the first place
- One pot open at a time. Most spills are a knocked pot, and one open pot is one thing to knock over.
- Let a section dry before painting its neighbor. Acrylic sets in minutes, so this costs almost nothing and prevents most smudging.
- Rest your hand on a folded sheet of paper. It protects finished areas and steadies your hand at once.
- Test on scrap first. Two numbers can look identical in the pot and clearly different dry.
- Keep the water jars away from the paint side of your working area.
Acrylic on everything else
- Clothing. Rinse under cold running water immediately and wash. Once acrylic has dried in fabric it is effectively permanent, which is worth knowing before you sit down in a favorite sweater.
- Skin. Soap and warm water while wet. Dried paint on skin flakes off on its own within a day and does not need solvent.
- Table or floor. A damp cloth while wet. Dried acrylic on a hard sealed surface can usually be lifted with a fingernail or a plastic scraper.
- Brushes. Wash before the paint sets. Dried acrylic in the base of the bristles splays a brush permanently.
Finishing up
Once the repair is dry the canvas is ready to continue. If you want to protect the finished piece, let the whole painting cure for several days rather than just until it feels dry, then consider a matte varnish, which also evens out any difference in sheen between the repaired patch and the rest.
Ledgebay kits ship with vacuum-sealed acrylic paints, brushes in a range of sizes and the 11 x 17 reference print, on pre-primed cotton canvas rolled in a tube rather than folded. If a color runs low while you are patching, there are matched extra paint sets for every design, which is the practical fix for using up a color on repairs. The full catalog is here, and custom paint by numbers from a photo works from a picture you upload.
For hanging the finished piece, see how to frame a paint by number canvas.
