If you can remove them with out mangling them up and they are not badly squashed you can Heat them red hot and drop them in water and that softens them.

However, you cannot do that to the Fuel Injection Pump Crush Washers or Aluminum Crush Washers.
Depending on the size the US sized Copper Cush Washer will work. Harbor Freight sells an assortment.
Ace Hardware sells the US sized ones individually.

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84 300D, 82 Volvo 244Gl Diesel