It is true that this is explained in the Mishna Berurah (Siman 308, 3). However, today, when a package of 1000 pages is sold for pennies, paper does not have the same significance as it once did, and one cannot say that the paper is considered Muktzah Machmat Chisaron Kis (Muktzah due to financial loss). Rather, in my opinion, it should be said that the paper is Muktzah because it is a Keli Shemelachto L’Issur (a tool whose primary function is for a prohibited act), as this paper is not used for cleaning but only for writing.

There is a practical difference regarding which category of Muktzah the paper belongs to: if it were Muktzah Machmat Chisaron Kis, as Maran the Mishna Berurah wrote regarding the situation in his time, it would be forbidden to move it except in an indirect or unusual manner (Kil’achar Yad). However, if it is Muktzah because it is a tool whose function is for a prohibited act—as it would seem the law is in our times—it is permitted to move it for the sake of the object itself (to use it for a permitted purpose) or for the sake of its place (if one needs the space it occupies).