Walther SSP owners, what do you use instead of "Spezialfett" special grease? Any specific brand and type recommendation? Manual says to use only this super special secret lube and does not provide any information about substitute when you run out of it. Walther stopped selling it long time ago as it seems. I found some older threads about the same topic discussing that any silicone grease from a dive shop will work, but there was also opinions that it might not be a good idea to use it on aluminum surfaces. Common consensus is that the special grease is required to to o-ring seals in the air damper. Advice and opinions are welcome, thank you!