> Even though I'm not Allan, I'll give an answer: it's 'skál' as the most
> common version of the acusative, but 'skáli' is also acceptable as this
> version has been found in texts.

The second form is not familiar to me.
Perhaps you're confusing it with
the word 'skáli' meaning "hall".

The declension of 'skál' meaning "bowl"
is as follows:

nom. skál
acc. skál
dat. skál
gen. skálar

nom. skálar
acc. skálar
dat. skálum
gen. skála

"Mjök er brögnum bekkr
blíð-skálar þekkr."

Kveðja,
Haukur