Sorry
Missed this post
For aluminium crush washer, you have to very carefully use a high temperature torch
And as we know al doesnt show red/yellow shades when heated, we need to improvise to detect when to stop heating.
So get an oxy acy torch and first soot the washer up (blacken) or use a permanent marker to blacken it
Then start heating it up evenly till the black disappears, stop and cool it down.
There you go, ready for another life in service.