100 acetone or hydrogen peroxide are suitable alternatives if you do not have paint cleaner available.
Varnish stain on carpet.
Watch for loss of color.
Place the towel over the stain and allow it to rest for five to 10 minutes.
If the stain remains repeat the process but add 2 tablespoons of borax to the mixture.
Continue blotting until the stain begins to break down and dissolve.
Then press the damp material against the carpet repeatedly blotting up the stain as you go.
This will give the solvent time to dissolve the varnish.
Vacuum or blot up the excess.
Work from the outside edges of the spill towards the center.
Spray the stain and use a clean cloth to blot it up as the stain begins to loosen and lift from the carpet fibers.
Apply the mixture to the stain with a cloth.
If the stain was removed do not proceed to the next step apply ammonia mix to the stained area without soaking the carpet.
Oil based paint stains are more difficult to remove so it may take a while to fully dissolve the pigment.
A very effective general stain remover is a mixture of 2 tablespoons of salt and a cup of white vinegar.
Apply vinegar mix to the stained area without soaking the carpet.
Wet a cleaning cloth with a bit of paint cleaner and start blotting the area.
If what you have available is pure ammonia work more cautiously and dilute a teaspoon into in a cup of water before dabbing it onto your carpet.
Blot or gently stroke the carpet pile.
Let the area dry and then vacuum the area.