Post War Lend-Lease Actions
I have a very good Russian book "Lend-Lease Tanks" by M.Kolomietz and I. Moshchanskij that covers this subject very well. In short...
Per the Lend-Lease agreement all military items received by the USSR were to be returned to the lender. Most trucks received capital repairs and were returned to the Americans in 1947. Because Stalin sees the US and Britain as the next enemy, tanks were declared scrap and for the most part they were pretty beat up. I doubt they could have been put in usable shape given the lack of spare parts, etc. Thus, they were not returned but some did make it into the hands of future Warsaw pact brother countries.
The US demanded the lease payments of 2.6 Billion USD but lowered it to 1.3 Billion USD. In 1972 the situation was resolved when the USSR agreed to 722 Million USD which were to used as trade credits, etc. rather than outright cash. Problems with trade agreements gave the USSR reasons not to pay or advance the agreed sum. This last section was a bit fuzzy in the book and you should probably check it out on the Internet once you lay your dice aside (right).
The book has great pictures and as a military scale modeler I have used it for markings on the 1/72 tanks I build when not playing ASL. A Russian decal company used the pictures for a couple sets of "Lend-Lease" decals which are quite good.