An appraisal of stock has found some items have an uncertain provenance while others are in a "poor condition".
Curators have compiled a list of items that could go at Brecknock, Powysland, Llanidloes and Radnorshire museums.
A decision will be taken by councillors at a meeting on Thursday.
"The museums accept that one of its key functions is to acquire artefacts and to keep them for posterity," said the report.
"In recent years staff have followed a strict collecting policy, however, historically a number of items, often with uncertain provenance and sometimes in extremely poor condition have been taken into the collection.
"The main driver for the collection review was to reappraise items and to assess their suitability for long-term preservation.
"There are no financially motivated reasons for disposal of any items."
Old bottles, bikes and blacksmith's bellows are among the items that could be disposed of amid plans to cut back on museum collections, according to Powys council.