As nouns the difference between metts and meths
is that metts is plural of mett while meths is short form of methylated spirit.
metts
English
Noun
(head)
meths
English
Etymology 1
Shortened from (methylated spirit).
Noun
(-)
(chemistry) Short form of methylated spirit.
Etymology 2
From (meths) or (methylated spirits), as stereotypically drunk by tramps.
Noun
(head)
(Geordie)