Question about dry ice

What for? It is a highly efficent method of separating trichomes from bud without heavy manipulation/degradation or chemical solvents. For the purest, cleanest truchomes know to man use dry ice. Or really cold co2 as I call it. What for? Why not!

What for? It won't magically make any extra THC appear from thin air.

don't know about UK but supermarkets in usa have it. pellet form would be best, but you can chisel a block just as easily.. use some of the mesh bags you see for bubble hash.. pop it in there, let it get cold and shake it over a flat surface you can easily scrape it together afterward. it's much faster than ice hash, but you get a hell of a lot more chlorophyl contamination and you decapitate the trichomes alot more too, which makes it less enjoyable smoke by comparison... but bubble hash of any amount worth running takes 2.5-3 hours if you are good at it and have 2 batches of cold water and multitask scraping with washing (mini rv washer highly recommended) - 10-12 cycles are needed to get most of the potential yield. the ease of dry ice hash can definitely make it a better choice depending on personal preferences.

Wraap a sock on the nozzle n blast away to catch the ice.

The fire extinguishers with just co2.

To find it locally check with grocery stores or meat processors, they sometimes carry it-especially if they do shipping. It comes in both block and pellet forms. If you find a place that had it, bring a cooler to make transporting it easier/safer. Exercise extreme caution handling it, it will cause frost burns on bare skin.