From BiblePortal Wikipedia

Wilson's Dictionary of Bible Types [1]

 Psalm 75:8 (a) This is a picture of the bitterness of the wrath of GOD in its worst form and character. The teaching that a "loving GOD will not punish sinners" is repudiated by this statement. The wicked will suffer the punishment of GOD to the last drop.

 Isaiah 51:17,  Isaiah 51:22 (a) In this place the fury and the wrath of GOD have been poured out on Jerusalem to the last drop. GOD punished Israel in great wrath because they turned against Him in such a wicked and evil way.

King James Dictionary [2]

Dregs n. Plu. Gr.

1. The sediment of liquors lees grounds feculence any foreign matter of liquors that subsides to the bottom of a vessel. 2. Waste or worthless matter dross sweepings refuse. Hence, the most vile and despicable part of men as the dregs of society.

Dreg, in the singular, is found in Spenser, but is not now used.

Easton's Bible Dictionary [3]

 Psalm 75:8 Isaiah 51:17,22

American Tract Society Bible Dictionary [4]

See Lees .

Cyclopedia of Biblical, Theological and Ecclesiastical Literature [5]

( שְׁמָרַים , Shemnarim' , lees of wine [as everywhere rendered except in] Psalm lxxv. 8; so called from settling or being kept; קֻבִּעִת , Kubba'Ath ,  Isaiah 2:17;  Isaiah 2:22, means a goblet-cup merely). (See Lees). The best wines of the East are much mixed with dregs, in the vessels in which they are preserved, so that commonly when drawn out the liquor is strained for use. It is to this condition of the wine that the Psalmist appears to refer: "He poureth out of the same; but the dregs thereof, all the wicked of the earth shall wring them out and drink them" ( Psalms 75:8). This is probably intended to denote that the pure and clean wine should be given as a wine of blessing to the righteous, while the wicked should drink the thick and turbid residue. The punishments which God inflicts upon the wicked are compared to a cupful of fermenting wine mixed with intoxicating herbs, of which all those to whom it is given must drink the dregs or sediment. The same image occurs in several Arabian poets. Thus Taabbata Sharran says, "To those of the tribe of Hodail we gave the cup of death, whose dregs were confusion, shame, and reproach." (See Wine).

International Standard Bible Encyclopedia [6]

dregs  : The "sediments," "lees," "grounds of liquor"; only in plural. In the King James Version it stands for: (1) Hebrew ḳubba‛ath , "bowl," "chalice," found only in  Isaiah 51:17 ,  Isaiah 51:22 : "the dregs of the cup of trembling"; "the dregs of the cup of my fury." the Revised Version (British and American) correctly changes "dregs" into "bowl." (2) Hebrew shemārı̄m , "sediments" or "dregs," especially lees of wine. "The dregs thereof, all the wicked of the earth shall wring (the American Standard Revised Version "drain") them out and drink them" ( Psalm 75:8 ), i.e. God gives to the wicked the cup of wrathful judgment, which they must drink to the last drop.