Keresone heaters blowing out blue smoke

Hi, been a while since I been here.

I've got three kerosene heaters all from Dainichi, and all three simply blow out blue smoke. Fortunately, they went out towards the end of winter, but in spring cleaning, and deciding what to throw out and what to keep, is there a way to get these heaters working properly again without paying an arm and a leg? Or would it be better just to send 'em to recycling and buy new heaters?

Never heard of the blue smoke problem but that definitely doesn't sound safe... Might wanna dump those and just get new ones. Personally I like the electric ones better for heating purposes simply because the refilling process is a pain imo lol. Not to mention they are much cheaper cost-wise than the heavier kerosene versions.