Or...you could use D'Addario EJ51 recording strings on your classical guitar like I do. These are lightly polished to reduce the wound string humps. They work beautifully and lessen the squeak considerably.
Good tips, BTW.
Mark
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'73 Washburn W240 (Finished!)
'08 Washburn D10SCE
'08 Washburn D10QBK (Son's)
'09 Washburn C104SCE Classical
'89 Washburn C10N Classical
'73 Sivertone Model 319