I have been practicing chakra sadhana for 1 year, not regularly. I get some mint feeling in the chakra locations and one more thing i suddenly see a bunch of small sized rhombus shapes/some times no shapes just plain area floating in the air with Smokey gray color; Which lasts for a second and disappears.
You are experiencing the natural function of the body being purified. Keep your awareness in stillness and allow these things to just happen without focusing on them. They will develop and transform and stillness will go bigger and bigger and deeper and deeper.