The only way to do that is to add each display body to a physicsBodies table whenever you add to physics:
local physicsDisplayObjects = {}
...
function scene:createScene(event)
...
local displayObject1 = ... -- display object
physics.addBody(displayObject1, ...) -- transform it into a physics body
table.insert(physicsDisplayObjects, displayObject1)
...
end
...
function something()
...
for i,obj in ipairs(physicsDisplayObjects) do
physics.removeBody(obj) -- revert obj into regular display object
end
physicsDisplayObjects = {} -- clear
...
end
...