Today, there can be found as many as twenty dolls nested together on ebay. The name of this traditional type of doll, Matroyshka, comes from the Latin word for mother and is a popular feminine name in Russian villages. In the 1890 s, A.I. Mamontev established a studio called Children s Education Workshop . He built it on his estate, Abramtsevo, which is near Moscow.  The dolls are uniquely Russian. Try finding dolls that were made just before the collapse of the USSR. They may be the most valuable of collectors items. Some vintage dolls  may just need some minor help to restore them to a valuable keepsake.
  There are many internet sites that offer a wealth of information about how the dolls are made and the various types available. What they don't tell you is how to repair minor flaws before selling or after buying one on ebay so here are some tips for the collector increase their value;

1. Cracks - These often occur when the wood is subject to climate change in shipping; less often due to flaws during construction. With a popular glue, such as Elmer's, press outwardly slightly where the crack is and use a fingertip to press a small amount into the inside of the crack. Press together and wrap a rubber band around the outside to compress. Wipe any excess glue off with a rag and let harden overnight. If there is any shiny spots at the crack, use very fine grade 0000 steel wool to buff the wood in side. Do not use sandpaper.

2. Binding - If the dolls are difficult to separate, again it may be due to climate expansion. I use rubberized shelf liners to twist and torque the difficult dolls apart. Then, again with fingertip, rub talcum or baby powder along the inside top rim. Twist and repeat until dolls part freely, then wipe away any excess powder.

3. Blemishes - Minor blemishes or surface flaws are usually confined to the lacquer, since it applied in many coats. Moisten a Q-tip with paint thinner (or nail polish remover) and VERY carefully rub the blemish. If any paint appears on the Q-tip STOP. You have gone as far as you can go. If the area is still slightly rough; again use the 0000 steel wool to even the roughness as best you can. To conceal the repair, rub vegetable oil over it and let dry.

4. Staining - It's not uncommon for vintage dolls to dull because of exposure to chimney or tobacco smoke over the decades. If the vivid colors are now dull, mix a very diluted solution of Murphy's wood soap and carefully wipe a less obvious surface area with a rag. Again, if paint comes off, STOP.

I hope this guide helps you in your collecting over ebay.  Good luck!