Dry sift will be a safer option since it doesn't involve a flammable solvent but dry ice can be hard/expensive to source sometimes depending on where you live. Ice water hash is an option too though the yields aren't as good. With dry sift/bubble hash quality can vary depending on how aggressive you agitate, more/less plant matter makes it in. With BHO it's mostly about not blowing yourself up lol....do it outside. You'll want to purge under vacuum to remove as much solvent as you can.