If you can, it could be worth removing the element, scrubbing the ends with something that will remove any clag, rinsing well and then baking it in the oven at,say, 150C to dry it. I did this for several clagged-up elements some years ago and they're all still OK.
Max permitted for IT equipment RFI suppression is 0.75mA, IIRC.
If designing a circuit for 10mA leakage, in the old regs it would have to be a high integrity earthing circuit, which was not the normal arrangement for a domestic ring circuit, although it could be made so by connecting the two ends of the CPC to different earth terminals in the CU. Also max design leakage for an RCD was 1/4 of its rating, which is 7.5mA for a 30mA RCD.
So I would say 10mA is well outside permitted, although I don't have the relevant EN which lists the values for white goods. It's probably the same as for IT equipment.
If it also has a conventional grill or fan oven, you could try running those for a bit and see if drying out improves it any.
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