Possible Clues:

• Tsar's necessary after turn of century and easily dealt with
• Problem-free? That can't be said of falling currency!
• Isn't money in Moscow easy!
• Don't worry - it's not in current use in Russia
• It's easy for this apparently to be worthless in Russia
• Not worthwhile in Russia, but don't mention it
• Don't worry about its not being worth much in Russia
• Don't worry, it's not spent in Russia
• Not in Russian currency? That's OK
• Don't bother - it isn't worth anything, except in Russia (2, 7)