I have an interest to swap these banknotes for coins or another banknotes:
Approximate value to indicate the level of them is:
25 latu 1928 = 40 euro each (Catalog price shows VF=200$)
5 lati 1940 = 40 euro (Catalog price shows VF = 150$).
But all depends on your offer, because I do not stick to the figures.
Bright ideas like "my recent 2 euro's CC are worth of 8 euros, so let's swap this banknote for 5 x 2 euro CC which makes 40 euros together" will not work.
If interested, please PM me. Not necessary to make the negotiations public.