Fresh sloes: ring cut around the sloe and drop into a demi cover with chosen alcohol - gin, vodka and white rum work well.
Leave for 1 month, then pour liquid off the sloes, add 1kg sugar. shake daily for a few weeks until absorbed. Taste, if too dry add sugar too sweet add more booze
Frozen sloes: allow to defrost, press gently with a spud masher and put into demi, follow method for fresh.
Worked for me
People assume that Brewing is a strict progression of cause to effect, but *actually* from a non-linear, non-subjective viewpoint - it's more like a big glass of wibbly wobbly... beery weery... stuff.