Robert Young's Analytical Concordance gives machah as the word in both Isaiah 43:25 and Isaiah 44:22 (and occurring a total of sixteen times in the Hebrew Bible) :
I -- I am He who is blotting out thy transgressions for Mine own sake, And thy sins I do not remember. [Young's Literal Isaiah 43:25]
I have blotted out, as a thick cloud, thy transgressions, And as a cloud thy sins ... [Young's Literal Isaiah 44:22]
Biblehub shows moheh for Isaiah 43:25 and mahiti for Isaiah 44:25 each word occurring once in all of scripture, both being inflections of machah Strong 4229.
Taking Robert Young's rendering of Isaiah 43:25 the Lord repeats 'I' in emphasis. 'I' - 'I' am he that is ... So it is the Lord himself who 'blots out'. But to 'blot out' on paper is to leave a massive stain on the page - a dark remembrance of what was guiltily there.
How could one ever forget ?
Unless one pays attention to the repeated 'I'. It is he, himself, who stands in the way. One cannot see past the Almighty. One cannot reach the ends of his limits to 'peer around the corner' at what is 'behind his back' - if I might put it so, with due reverence.
This is apparent, also, in Psalm 32.
Blessed the man not does impute Jehovah iniquity ... [Biblehub Interlinear Psalm 32:2]
'Jehovah' on the very page, stands between 'the man' and 'iniquity'.
It is the Lord, himself, who prevents one seeing one's own sin. He stands in the way. His presence prevents one's view from envisioning. Thence the blessedness.
The concept is seen in Acts 3:19 when Peter, perhaps, alludes to this very verse :
Repent ... and be converted ... that your sins may be blotted out, when the times of refreshing come from the presence of the Lord. [Acts 3:19 KJV]
It is the presence of the Lord which will be responsible for the refreshing times when sins will be 'blotted out'.
But aleipho (nine times in scripture) means 'to anoint' and thus exaleipho (five times in scripture, once here in Acts 3:19) cannot mean 'blot out' (with more oil ? ?). In other places 'wipe away' has been used as of tears in Revelation 7:17 and 21:4.
But I suggest that the source of the tears will be dried up. Not that tears will be wiped off the cheeks as they drizzle down, for then the subject of the Lord's gracious ministration . . . is still weeping !
I suggest that the tear ducts will no more have a cause to form tears in the first place.
'Remove' all tears from the eyes - is, I suggest, the concept ; they being impossible to form.
And 'remove from view' is what I suggest is the effect of the Lord Jehovah standing in the way of one's sins, making them impossible to view.
Does the Hebrew of Young's quoted machah (Biblehub's reference to both moheh and mahiti) allow of such a rendering ?
Do we need a better concept than the image in the mind of a massive blot of ink being smeared over some writing, leaving an indelible stain to remind oneself of one's transgressions ?