And, in many cases, the fill from the suits themselves. Beta cloth has a geometric albedo of around 80%. In the Apollo 11 video you can see a marked effect when Armstrong walks out of the LM shadow into the sun to photograph Aldrin's egress.
Oddly enough, the reflected light from the lunar surface is an effect I demonstrated live on television, for BBC Channel 4. David Percy of Aulis was invited (twice) to appear on that program with me to defend his claims, but he declined.
David Percy will not acknowledge his critics or address demonstrations of his errors. He only wants the money.