Hi Matt
as Tom stated we too see new lubricant up to an ISO 20/15 in contamination levels,
with hydraulics we think always filter new oil before applying,
if filtration is not easy then if 205 litre drums are decanted in a horizontal position and not distrurbed, after 4-5 days all significant debris will be settled on the "bottom" and the lubricant when decanted is an ISO 16/13 or better,
drums must not be moved and left in position when decanting for this to occur and the last 10 litres in the drum should be discarded.
Cant rely on new oil always being clean,
always check or filter before applying
regards
Rob S
www.rttech.com.au