My last find while digging for potatoes in 2009:

France, Paris mint, 1943 AD., Vichy French State issue, engraver: L. Bazor,
1 Franc Aluminium (23 mm / 1,37 g),
Obv.: ETAT FRANCAIS / LB -monogram in right field , a 2 sided Battle Axe, flanked by wheat stalks.
Rev.: • TRAVAIL • FAMILIE • / • PATRIE • / 1 / • FRANC • / 1943 , oak leaves and acorns flanking the denomination.
KM 902.1 .
Mintage: 205,564,000
The garden gets household compost since 60 years. So a lot of dirt from the house containing some small change will meet the potatoes.