For the formula, input:
TRIM(SUBSTITUTE(\
SUBSTITUTE(\
SUBSTITUTE(\
SUBSTITUTE(\
SUBSTITUTE(\
SUBSTITUTE(\
SUBSTITUTE(\
SUBSTITUTE(\
SUBSTITUTE(\
SUBSTITUTE(\
SUBSTITUTE(\
SUBSTITUTE({!Loop_Through_Donations.npsp__In_Kind_Description__c}, '"', '"'),\
''', "'"),\
'&', '&'),\
'</p>', ' '),\
'<span style="color: rgb(68, 68, 68);">', ' '),\
'</span>', ' '),\
'<span style="color: rgb(62, 62, 60);">', ' '),\
'<span style="font-size: 14px;">', ' '),\
'<p>', ' '),\
'<br>', ' '),\
'<br />', ' '),\
' ', ' ')\
)