Pale caps darkening with age; pale brown gills becoming rusty brown as it matures.  The cap cuticle (skin) is rubbery, elastic and translucent; it can easily be peeled away from the flesh and stretched to double its size - this helps to distinguish it from other Crepidotus.  

other Crepidotus

Identification is difficult, either requiring microscopic examination or a photogrpah of the peeling cap cuticle. If you have not done this or if the specimen has not been examined by an expert, please submit your record as genus only (Crepidotus).

Trunks, branches and stumps of dead broadleaved trees.

Late summer and autumn.

Widespread and fairly frequent in Britain.

Status in Leicestershire and Rutland not known.

https://www.first-nature.com/fungi/crepidotus-mollis.php