Recycling of pre-consumer waste toner is practiced by most manufacturers. Classifying toner to the desired size distribution produces off-size rejects, but these become valuable feedstocks for the compounding operation, and are recycled this way. Post-consumer waste toner appears primarily in the cleaning operation of the photo-printing machine. In early printers, as much as 20 to 25% of feed toner would wind up in the cleaner sump and be discarded as waste. Improved printer efficiencies have reduced this waste stream to lower levels, although on average 13% of the toner in each cartridge is still wasted. Some printer designs have attempted to divert this waste toner back into the virgin toner reservoir for direct reuse in the printer; these attempts have met with mixed success as the composition of the toner will change by expending fusibles while retaining developer particles. Some consideration and fewer industry attempts have been made to reclaim waste toner by cleaning it and "remanufacturing" it.