Wash bottle in hot soapy
water; rinse well and dry thoroughly.
Give the bottles
a coat of flat paint for base - ivory is good. Let stand
to dry overnight.
Fill with water to about 4 inches
from the top. Now put a few drops of each of several colors
of quick-drying enamel on top of the water. The enamel will
float. Flatten out the drops on the surface by gently blowing
on them. Holding the bottles by the neck, as close to the
top as possible, dip it down into the water, twisting bottles
as you dip. The bottles will pick up the colors on top of
the water as it is lowered, so make sure you use a smooth
continuous motion - don't stop part way. Give the bottles
a twist as you dip them, creating a swirl of color. Carefully
remove from the water and set it on a newspaper to dry.
When the bottles have dried, give the surface a luster
with wax and polish.