"The mattress is very easy to remove and replace, just four screws for
the fold out and snaps for the mattress portion at the back.  Just as
easy to replace..."

... I used a towel to rest my elbows on while messing with the screws back
there. The upper bed is hard enough with the mattress on it, to sleep on;
it's REALLY uncomfortable without! A "quality problem", though ;>)

bob