Here is the abridged low-down on plucking base metal bullion from dealer junk boxes and the like. Not everything is listed, just the ones I seem to find most often. Whether or not the coins I list are economical to buy depends on the price they sell for at your specific location and the spot price of the metal. I just list the coins - you can figure it out the rest yourself. You may not mind slightly over-paying for .999 nickel, since it normally sells at a small premium in coin form, but that's a personal choice. Also, its possible some of these coins may have numismatic value in excess of their metal value.
4.5-4.59; g Canada 5 Cents (1922-1942, 1946-1950, 1955-1981)
7.5 g; French 2 Francs (1979-Euro)
6 g; French 1 Francs (1960-Euro)
4.5 g; French 1/2 Francs (1965-Euro)
10 g; Netherlands 2 1/2 Guilder (1969-Euro) '66 and earlier silver
6 g; Netherlands Guilder (1967-Euro) pre67s and some '67s are silver
3 g; Netherlands 25 Cent (1948-Euro)
1.5 g; Netherlands 10 Cent (1948-Euro)
7 g; Belgium 50 Franc (1987-Euro)
Greece 10 Drachma (1959)
5.73 g; Hungary 5 Florint (1971-1983)
6 g, 10 g, & 15 g; French Polynesia 10, 20, & 50 Francs (1967-2000+)
6.9 g; Bahamas 25 Cent (1966-1989)
Impostors to avoid:
French 5 Franc (1970-Euro) Nickel-clad CuNi
Belgian 1 Franc (1989-Euro) Nickel-plated iron
Various Icelandic coins are nickel-clad steel
Italian 50 & 100 Lire (1954-1989) stainless steel