Hi! My Sievert torch flame has gradually lost power over the last month or so and then just went out during use! I’ve taken it apart and I think the head is blocked (as I can’t blow through it!) I have boiled it and scrubbed it with a toothbrush but still no flame. Does anyone have any suggestions or should I just buy a new head? I’ve only had the torch about 2 years and I definitely haven’t run out of gas!