Carry a copy of your declaration with you. You may need it when you depart the country. Do not carry parcels or letters on behalf of third persons. In general, do not transport these currencies across international borders. Currency regulations in Eastern Europe change frequently.
Some countries have a dual exchange rate.
Before you go, learn the most advantageous way to handle your purchases by inquiring about exchange rates and currency regulations from your travel agent or the embassies of the countries you plan to visit. Travelers may be asked to declare the amount and kind of currency they carry. Purchase currencies only at officially authorized exchange facilities in the country of issue and retain your receipts. Do not engage in private currency transactions or sell personal property. While U.S. dollars may be exchanged for Eastern European currencies, it is difficult or impossible to reconvert those currencies to dollars or another hard currency.