In the name of Allah, the Most Merciful, the Bestower of Mercy.
Imam Ibn Bāz (rahimahullāh) was asked: Is it allowed to shake hands with a woman over 50 years old and for her to discard her outer garment (hijāb or jilbāb)?
Answer: It is not allowed for a woman to shake hands with men, even if she reaches 50 years of age or 60 years due to the saying of the Prophet (salallāhu ‘alaihi wasallam): “Indeed, I do not shake hands with women.” And Ā’ishah (radiyallāhu ‘anhā) said: “By Allah! The hand of the Messenger of Allah (salallāhu ‘alaihi wasallam) did not touch the hand of any woman ever. And the women only gave their pledge of allegiance by words.” So it is not allowed for a woman to shake hands with unrelated men (non-mahrams) regardless of whether she is young or old. As for her mahrams, then there is no harm, such as her brother, her paternal or maternal uncle, or with other women―there is no harm in this.
And likewise, it is not for her to uncover her face  unless she is from those women who have passed the age of child-bearing who do not expect wedlock (al-qawā’id), an old woman, advanced in years who does not expect to be married, and she is not one who displays her adornment, then there is no harm―but remaining upon modesty and covered is better for her due to the saying of Allāh, the Most High:
وَٱلْقَوَٰعِدُ مِنَ ٱلنِّسَآءِ ٱلَّـٰتِى لَا يَرْجُونَ نِكَاحًا فَلَيْسَ عَلَيْهِنَّ جُنَاحٌ أَن يَضَعْنَ ثِيَابَهُنَّ غَيْرَ مُتَبَرِّجَـٰتٍۭ بِزِينَةٍ ۖ وَأَن يَسْتَعْفِفْنَ خَيْرٌ لَّهُنَّ ۗ وَٱللَّهُ سَمِيعٌ عَلِيمٌ
“As for women past child-bearing who do not expect wed-lock, there is no sin on them if they discard their outer garment in such a way as not to show their adornment. But to refrain from that is better for them. And Allah is the All-Hearer, All-Knower.” (An-Nūr: 60)
So this refers to women who have no desire for marriage and that desire is not seen in them due to their old age. Another condition stipulated is that they do not display their adornments, whether it be by applying kohl, or perfume, or wearing beautiful garments―this is not permissible. As for the old woman who does not display her beautifications, she does not desire marriage and she is elderly, then there is no harm if she uncovers her face in front of men because there is no desire in her and there is no fear of fitnah, not for her and from her. However, modesty and keeping her face covered is better because every relaxing [of the hijāb] is a catch [for someone] and some people may be put to trial. For this reason, Allah stated: “But to refrain from that is better for them.” So if it is better for the elderly lady to adhere to modesty, how much more so for the young woman?
So the hijāb is wājib, necessary except for the woman advanced in years who has no desires and does not wish to be married, and alongside that she does not display any beautification―then for her, there is no harm if she discards her outer-garment (cloak or jilbāb) however modesty is better for her and to maintain her hijāb.
Source: نور على الدرب حكم مصافحة المرأة للرجال إذا قد بلغت خمسين سنة
 This is for those who hold that the niqāb is wājib. Read here: “Al-Albāni on the Niqāb of the Muslim woman, whether it is wājib or not, the permissibility of uncovering her face and hands―and the danger of displaying her beautifications in public.“
All praise is due to Allah, Lord of all creation, and may the peace and blessings of Allah be upon our Prophet Muhammad, his family and all his Companions.