French gardening! 😊

Hi, I was wondering if you could give me an idea how to clean these and if anyone knows about them please. I found them whilst gardening in France. Many thanks in advance 

1.  

2.  

3.  

4.  

3. Second image has lettering CINQ CENTIMES 

N#485 [25 mm] 

4. Second image has lettering FRANCIAE ET NAVARRAE REX 

N#5466 [29 mm] 

1. Date 1780 at top of first image and may be the same coin as number 4 

2. May be one of these three: 

N#54336 [1639-1641] 

N#54337 [1640] 

N#54338 [1640-1643] 

GASTONVS V D LA SOV DOM or similar 

 DOVBLE TOVRNOIS then the date 

In my fathers flight diary from the second world war when he went gardening in France it was to drop mines in the water off the Atlantic coast near Brest.

Thank you much for your help! 😊 How would I go about cleaning these as they're really grotty! 

I can't speak for others but it is important to try to identify exactly what you have in order to determine what their possible value may be and their respective compostion before proceding to recommend anything. Which is what ZacUK is attempting to identfy for you.  Many of us are reluctant to advise any coin be cleaned at all, especially by a novice without making an educated decision on whether to proceed with cleaning or not . There are myriad ways to do so and everybody has their opinion on how to do so if you decide to proceed. Ketchup, Lemon juice. Salt water and vinegar, etc, etc. All  methods can be detrimental to value, if any.

Ok thank you very much. I'll not attempt cleaning! 😊